MARINE RESOURCES IN THE MESOLITHIC AND NEOLITHIC AT THE GROTTA DELL’UZZO (SICILY): EVIDENCE FROM ISOTOPE ANALYSES OF MARINE SHELLS*

Oxygen isotopes in shell carbonate samples from the marine rocky‐shore intertidal gastropod Monodonta turbinata (Born) are investigated in both modern analogue specimens and in archaeological specimens from the Grotta dell’Uzzo (Sicily). Variations in shell edge values of δ¹⁸O in living specimens collected monthly over two years are closely correlated with monthly seawater temperatures measured at the time of collection, showing that the species can be used for palaeoseasonality studies. Analyses of shell edge δ¹⁸O values in archaeological specimens, from Mesolithic through to early Neolithic phases at the Grotta dell’Uzzo, enabled the inference of various seasons of collection of shellfish and how such seasonality varies between the different phases of occupation. Interesting similarities and differences exist between the seasons of marine shellfish exploitation and the seasons inferred from the vertebrate zooarchaeological assemblages. A major inference drawn from the analyses and discussion is that the exploitation of all marine resources (fish and shellfish) increased in the later Mesolithic and early Neolithic periods.     

Stable isotope analysis of 14 individuals from the Mesolithic cemetery of Vasilyevka II,Dnieper Rapids region,Ukraine

Bone collagen extracted from 14 humans from the Mesolithic cemetery of Vasilyevka II was analysed for their δ¹³C and δ¹⁵N ratios. This cemetery is one of only two later Mesolithic cemeteries from the Dnieper Rapids region, being dated to 7300–6220 cal BC on the basis of three radiocarbon determinations. This analysis provides insights into the nature of the diet of the Dnieper populations at the very end of the Mesolithic period, prior to the adoption of pottery in the region, and the assumed shift towards the exploitation of domesticates in the economies of the populations of the Dnieper region, and considers these in relation to broader temporal indicators of diet in the region.     

Oxygen isotopic composition of limpet shells from the Beagle Channel: implications for seasonal studies in shell middens of Tierra del Fuego

Shell middens distributed along the coastal areas of the Beagle Channel (Tierra del Fuego) testify the primary role of marine resources in the successful social dynamic of hunter–gatherer–fisher societies (HGF) in extreme high latitude environmental conditions. Intertidal and subtidal limpet species are frequently identified taxa of these archaeological deposits. We investigated whether shell δ¹⁸O of the limpet species Nacella deaurata is a valuable record of local sea surface temperature (SST) and ambient water δ¹⁸O (δ¹⁸Ow) fluctuations, and in turn can be used to estimate the season of its exploitation by Holocene HGF. Sequential shell δ¹⁸O of modern species track seasonal changes of SST and δ¹⁸Ow. The comparison of shell δ¹⁸O profiles of N. deaurata and Nacella magellanica (a coexisting species) suggests the occurrence of distinct growth rate and physiological adaptations between species. Shell δ¹⁸O of zooarchaeological specimens of N. deaurata from Lanashuaia II suggests that animals were exploited predominantly in winter and that experienced similar environmental conditions of present day at ∼1320 years BP. Results also indicate that N. deaurata is a valuable candidate for studying past seasonal changes in SST and δ¹⁸Ow in this southernmost part of South America.     

Mapping Mesolithic and Neolithic cultures behaviours and interactions with nature and properties of rocks in Western France

Multivariate statistical methods are used to study recent Prehistory lithics from the Armorican Massif, allowing us to classify them in more or less distinct groups according to the structural and mineralogical qualities of rock types involved. Analyses are carried out on metamorphic, sedimentary and magmatic rocks making up lithics collected from 31 localities. The petrographic properties are determined by polarizing microscope (POM), while the mechanical properties are obtained by Vickers's indentation method (VI), compression/traction (CT) and ultrasound echography (UE). The results provide us with important information about the management of lithic raw materials used by various human and cultural groups during the Mesolithic and Neolithic of the Armorican Massif. The more commonly used materials show a homogeneous and stable distribution of regional technology styles. The rock types exhibiting mature and homogeneous structures possess the better qualities for knapping (fracture energy G_Ic) and use (edge toughness M₁), and are more involved in exchange. The application of Upward Hierarchical Classification (UHC) and Principal Component Analysis (PCA) allows us to identify the classes of materials as well as the causes of variations of rock type abundance within the lithic assemblages of the Mesolithic and the Neolithic. In this way, we can then also predict the discovery of archaeological artefacts in areas lacking any known indications of the exploitation of outcropping materials.     

Oxygen isotope seasonality in a temperate estuarine shell midden: a case study from CA-ALA-17 on the San Francisco Bay,California

Seasonality determination using stable oxygen isotope (δ¹⁸O) analyses in archaeological mollusk shell has been largely limited to aquatic settings where one of the two factors that control shell δ¹⁸O – water δ¹⁸O (or salinity) and temperature – is assumed to be constant. Open coastal marine environments reflect the former situation, and tropical estuaries constitute the latter. In an effort to expand stable isotope seasonality to an ecological setting where neither variable remains constant, we present a model of annual shell δ¹⁸O cycle of aragonite deposition derived from instrumental data on salinity and temperature from San Francisco Bay, California. The predicted range of modeled shell δ¹⁸O is consistent with observed δ¹⁸O values in prehistoric and modern shells when local conditions are considered. Measurements of δ¹⁸O taken at 0 mm and 2 mm from the terminal growth margin were made on 36 archaeological specimens of Macoma nasuta from a late Holocene hunter-gatherer site CA-ALA-17, and season of collection was inferred using the shell δ¹⁸O model. We conclude that shellfish exploitation occurred through the year with the exception of fall, which may indicate scheduling conflicts with acorn harvesting or other seasonally abundant resources elsewhere. The model supports the feasibility of stable isotope seasonality studies in temperate estuaries, provided that instrumental records are available to quantify the relevant water conditions at appropriate spatial and temporal scales.     

Computer simulations of the seasonal variations of the ionospheric equatorial anomaly in East Asia under solar minimum conditions

The previous dynamical, computer simulation model of the ionosphere at low latitudes of Chan H. F. and Walker G. O. (1984a, J. atmos. terr. Phys. 46, 1103; 1984b, J. atmos. terr. Phys. 46, 1113) has been modified to (1) include photoionization of molecular species NO⁺, N₂⁺ and O₂⁺ below 300km, (2) decouple the ionization and wind calculations below 180 km and (3) expand the geographical coverage to 46°N-30°S latitude. The first two modifications improved the model stability and the latter reduced the effect of the lateral boundaries on the equatorial anomaly. Results are presented for the representative seasonal months of January, April and July for East Asia, during solar minimum, comprising latitudinal-local standard time (120°E) contour plots of (1) the atmospheric pressure, (2) the computed meridional wind at 300 km, (3) the foF2 and (4) hmF2, together with latitudinal profiles of foF2 and N_T (electron content) showing the daytime development and nighttime decay of the equatorial anomaly.Comparisons have been made between the computer simulations and various experimental measurements of foF2, M(3000) F2 and N_T obtained in East Asia during periods of low solar activity. Most of the gross features of the development and decay of the equatorial anomaly at the various seasons were reproducible by the model simulations, the best agreement occurring for the equinoctial month of April.     

Seasonal Patterns of Coastal Exploitation on the Farasan Islands,Saudi Arabia

Here we present the results of the analysis of coastal exploitation patterns in the southern Red Sea during the Middle Holocene. We focus on the shell midden cluster of the Farasan Islands, Saudi Arabia, which comprises over 3,000 shell midden sites. These sites date from 6,500 to 4,500 cal BP and are part of an arid landscape. We focus on one site, JW1727, which provides a snapshot of marine exploitation and will help to understand the use of food resources within the region. Stable isotope values (δ¹⁸O) were collected from the marine gastropod Conomurex fasciatus (Born 1778), which represents 72% of shell weight of JW1727, in order to reconstruct the season of capture. Results demonstrate that 1) every season is represented within the dataset; and 2) there is increased C. fasciatus deposition during the summer and autumn months. This indicates a diet consisting of C. fasciatus throughout the year in combination with other food sources and an increase of the C. fasciatus component during the arid seasons, possibly linked to the unavailability of vegetation. Additionally, size measurements of C. fasciatus were carried out to examine changes in size distribution throughout the occupation of the site that could be related to overexploitation of C. fasciatus. However, no significant trends could be observed. In sum, the results suggest a sustainable and constant habitation of the Farasan Islands despite the highly arid conditions.     

Late Mesolithic burials at Casa Corona (Villena,Spain): direct radiocarbon and palaeodietary evidence of the last forager populations in Eastern Iberia

Current knowledge about the Mesolithic–Neolithic transition in the Central and Western Mediterranean European regions is deeply limited by the paucity of Late Mesolithic human osteological data and the presence of chronological gaps covering several centuries between the last foragers and the first archaeological evidence of farming peoples. In this work, we present new data to fill these gaps. We provide direct AMS radiocarbon dating and carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotope analysis were carried out on bone collagen samples of two single burials from the recently discovered open-air Late Mesolithic site of Casa Corona (Villena, Spain). The results shed new light on the chronology and subsistence patterns of the last Mesolithic communities in the Central Mediterranean region of the Iberian Peninsula. Radiocarbon results date the human remains and funerary activity of the site to 6059–5849 cal BC, statistically different from other Late Mesolithic sites and the earliest Neolithic contexts, and bridging the 500 yrs chronological gap of the Mesolithic–Neolithic transition from the area. Isotopic evidence shows that diet was based on terrestrial resources despite the proximity to the site of lagoon and marine ecosystems. This and previous isotope studies from the region suggest a lower reliance upon marine resources than for Atlantic and Cantabrian sites, although intra-regional patterns of neighbouring Mesolithic populations exhibit both fully terrestrial diets and diets with significant amounts of aquatic resources in them. We hypothesize that in the Central Mediterranean region of Spain the Late Mesolithic dietary adaptations imposed structural limits on demographic growth of the last foragers and favoured rapid assimilation by the earliest Neolithic populations.     

The role of shellfish in hunter–gatherer societies during the Early Upper Palaeolithic: A view from El Cuco rockshelter,northern Spain

The role of coastal resources in the subsistence strategies of Palaeolithic human populations has only recently become an important topic in Old World archaeology. Information on the exploitation of these resources, both as foodstuffs and symbolic elements, can be used to infer the emergence of modern human behaviour as well as to track the diversification and intensification of human diet over time. The excavations carried out at El Cuco rockshelter, located in northern Spain have provided evidence for the exploitation of marine resources during the Early Upper Palaeolithic. The accumulation of Patella shells at El Cuco provides the largest accumulation and the first clear evidence of collection and consumption of molluscs during the Aurignacian on the Atlantic Façade of Europe. A deposit of ornamental shells appeared in a very homogeneous context dated to the Gravettian, suggesting that the shells belonged to the same item. The analysis of this evidence has allowed us to conclude that marine resources were systematically used at least from the beginning of the Upper Palaeolithic in the region. However, a comparison with the Mesolithic shows that intensive shellfish gathering did not occur until the end of the Upper Palaeolithic. Regarding the ornaments, it is interpreted that the identified shell beads were used as social or personal status markers.     

Chemical analysis of 17th century Millefiori glasses excavated in the Monastery of Sta. Clara-a-Velha,Portugal: comparison with Venetian and façon-de-Venise production

A set of ten Millefiori glass fragments dating from the 17th century, originated from archaeological excavations carried out at the Monastery of Sta. Clara-a-Velha (Coimbra, Portugal), were characterized by X-ray electron probe microanalysis (EPMA), Raman microscopy and UV–Visible absorption spectroscopy. All glasses are of soda-lime-silica type. The use of coastal plant ash is suggested by the relatively high content of MgO, K₂O and P₂O₅, as well as by the presence of chlorine. Tin oxide or calcium antimonate were the opacifiers used in the opaque glasses, cobalt in the blue glasses, copper in the turquoise glasses, iron in the yellow and greenish glasses, and iron and copper were found in the opaque red and aventurine glasses. Based on the concentrations of alumina and silica four different sources of silica were identified, allowing the classification of the glasses into the following compositional groups: low alumina (<2 wt%), which includes a sub-group of cristallo samples with SiO₂ > 70 wt%, medium alumina (2–3 wt%), high alumina (3–6 wt%) and very high alumina (>6 wt%). Comparison with genuine Venetian and façon-de-Venise compositions showed that two fragments are of Venetian production, one of Venetian or Spanish production and the remaining are of unknown provenance. In two fragments the glass of the decoration is probably Venetian or Spanish but the glass used in the body is also of unknown provenance.     

Coast–inland mobility and diet in the Danish Mesolithic and Neolithic: evidence from stable isotope values of humans and dogs

Here we present the stable isotope ratios of carbon and nitrogen measured in bone collagen extracted from humans, dogs, herbivores and fish from Mesolithic and Neolithic coastal and inland sites in Denmark. Bones of freshwater fish from several Early Mesolithic lake-side sites have δ¹³C values surprisingly similar to those seen in marine fish. We propose a model, based on δ¹³C and δ¹⁵N, for the correction for both marine and hard water reservoir effect in radiocarbon dates. A strong reliance on aquatic protein is demonstrated for the Mesolithic inhabitants of the region from the middle of the Early Mesolithic onwards. A significant part of the protein in the diets of the dogs and humans from the Middle and Late Mesolithic was of marine origin, even at inland sites. This observation points to a high degree of (seasonal) coast-inland mobility. The isotopic evidence indicates that during the Neolithic small quantities of aquatic foods were still common sources of dietary protein.     

Alkaline cooking and stable isotope tissue-diet spacing in swine: archaeological implications

In this study we examine the effects of alkaline cooking on carbon and oxygen stable isotopic ratios of mineralized tissues from nine pigs raised on monotonous mixed C3/C4 vegetarian diets. Two sources of collagen (humerus and mandible) and two sources of apatite (humerus and enamel) were analyzed. Within each diet group, humerus and mandible collagens were found to record equivalent δ¹³C and δ¹⁸O ratios; however, enamel apatite was found to be enriched over bone apatite by 2.3‰ in carbon and 1.7‰ in oxygen. Alkaline cooking was found to slightly, but significantly increase the Δ¹³C_{collagen-diet} and Δ¹⁸O_{collagen-diet} of bone collagen. A similar trend towards enrichment was observed in bone and enamel Δ¹³C_apatite-diet and Δ¹⁸O _apatite-diet, but the differences were not significant. Observed isotopic shifts were consistent with increased nutrient utilization of the alkaline-cooked maize as compared to raw maize. In addition, a reexamination of the relationship between diet and tissue carbon isotopic values suggests that species and alimentary type should be considered when interpreting ancient diets.     

Oxygen isotopes in cellulose identify source water for archaeological maize in the American Southwest

Maize (Zea mays) was a primary food crop for aboriginal societies of the arid American Southwest. Water used for maize production in these arid zones could have come from precipitation and runoff during the summer monsoon, from perennial streams and springs, or from stored soil water fed by snowmelt. The oxygen stable isotope ratio (δ¹⁸O) of summer and winter precipitation on the Colorado Plateau naturally differ by more than 10‰ providing a powerful tool for distinguishing winter- from summer-derived water sources used in cultivation of maize. We investigated whether variation in δ¹⁸O of potential source waters is preserved in the δ¹⁸O of cellulose (δ¹⁸O_cellulose) of maize cobs by growing four aboriginal and one modern maize variety in pots irrigated with water of known δ¹⁸O composition. The δ¹⁸O_cellulose values of cobs ranged from 26.8 to 36.4‰ (averaged within varieties) and were highly correlated with δ¹⁸O values of the source irrigation water (−15.8 to −8.2‰). Cob δ¹⁸O_cellulose from five archaeological sites on the Colorado Plateau in southeastern Utah ranged from 27.3 to 34.6‰, closely matching the range of values observed in experimental plants. A δ¹⁸O_cellulose model developed originally for tree rings was parameterized and applied to the archaeological maize cobs. The model indicated that monsoonal precipitation accounted for 0–20% of the moisture for archaeological cob samples from a site adjacent to a perennial stream and 43–98% for samples from an upland site, more distant from a perennial water source. These results reveal the potential for using δ¹⁸O_cellulose to investigate prehistoric irrigation practices and source water used for maize production in the American Southwest.     

Implications of a freshwater radiocarbon reservoir correction for the timing of late Holocene settlement of the Elk Hills,Kern County,California

Uncertainties regarding the magnitude of freshwater radiocarbon reservoir effects can introduce random errors into dates on archaeological freshwater carbonates. As a result, many archaeologists avoid dating freshwater shells unless no other datable materials are available. The chronology of prehistoric occupation of the former Naval Petroleum Reserve No. 1 (NPR-1) at Elk Hills, Kern County, has been established with 50 radiocarbon dates on freshwater mussels (Gonidea and Anodonta sp.). Characterization of any freshwater radiocarbon reservoir effect is crucial for the accurate interpretation of inferred settlement and subsistence changes on the Elk Hills. Paired charcoal and freshwater mussels sampled from closely associated contexts were dated to identify a freshwater reservoir effect. Paired Anodonta and Gonidea sp. shells were dated to investigate interspecific differences in fractionation. Results indicate that a 340 ± 20 ¹⁴C yr correction should be applied to conventional ¹⁴C dates on freshwater carbonates in the Buena Vista Basin before calendar calibration. Evidence of interspecific differences is inconclusive. Dates recalibrated with the reservoir correction indicate that widespread occupation of the Elk Hills is correlated with increasing precipitation towards the end of the Medieval Climatic Anomaly and during the Little Ice Age, suggesting that slough resource exploitation may have been driven by regional population pressure rather than drought-related declines in aquatic productivity.     

Wild Food: Plants,Fish and Small Animals on the Menu for Early Holocene Populations at al-Khiday,Central Sudan

Al-Khiday, located on the bank of the White Nile in Sudan, offers an exceptionally preserved stratigraphic sequence, providing a unique opportunity to use organic residue analysis to investigate diet and subsistence during the Khartoum Mesolithic and the Early Neolithic, a period of nearly 3500 years (7000–4500 cal BC). While the vast and diverse Mesolithic fish assemblage indicates a strong reliance on products from aquatic habitats, floodplains, vegetated marshes, and open water, results from the lipid residue analysis suggest that the fish were not cooked in ceramic pots, but consumed in other ways. Rather, pots were more specialized in processing plants, including wild grasses, leafy plants, and sedges. These results, confirmed by experimental analysis, provide, for the first time, direct chemical evidence for plant exploitation in the Khartoum Mesolithic. Non-ruminant fauna (e.g., warthog) and low lipid-yielding reptiles (e.g., Adanson’s mud turtle and Nile monitor lizard), found in significant numbers at al-Khiday, were likely also cooked in pots. There is little evidence for the processing of wild ruminants in the Mesolithic pots, suggesting either that ruminant species were not routinely hunted or that large wild fauna may have been cooked in different ways, possibly grilled over fires. These data suggest sophisticated economic strategies by sedentary people exploiting their ecological niche to the fullest. Pottery use changed considerably in the Early Neolithic, with ruminant products being more routinely processed in pots, and while the exploitation of domesticates cannot be confirmed by a small faunal assemblage, some dairying took place. The results provide valuable information on Early and Middle Holocene lifeways in central Sudan.

     

Reading between the lines: δ18O and δ13C isotopes of Unio elongatulus shell increments as proxies for local palaeoenvironments in mid-Holocene northern Syria

The much debated link between the collapse of urban centres in northern Syria and climate change at the end of third millennium bc is arguably one of the best known cases about human societies' struggle with the unpredictable nature of the Holocene. Fine-grained analyses of bioarchaeological materials offer excellent opportunities to overcome some of the difficulties encountered in such studies that tackle the effects of changing environmental and climatic conditions on human civilisations during the Holocene. This paper explains the results of a pilot study that uses archaeological freshwater clams (Unio elongatulus) from northern Syria as intermediary anthropobiogenic proxies to infer about the seasonal rhythms of local pluvial regimes and their possible fluctuations at the turn of the third millennium bc. Having secreted their CaCO₃ in chemical and periodical accordance with the ambient environment and ending up at tell sites through human activity, these bivalves are suitable vessels of information about human ecology in northern Syria at the end of third millennium bc. Marked differences were observed between the isotopic (δ¹⁸O and δ¹³C) compositions of shells from Tell Mozan, an urban site that continued to exist throughout the rapid climate event, and those from Tell Leilan, which went into hiatus at the end of third millennium bc. These results have important implications about the potentially severe effects of micro-environmental differences on distinct human communities inhabiting the same culturally unified region.     

Estimating meagre (Argyrosomus regius) size from otoliths and vertebrae

This study presents a method for predicting meagre (Argyrosomus regius) body size (total length) from otoliths and vertebrae recovered from archaeological sites. The method involves regression equations calculated from a reference collection of 36 meagre skeletons and 113 meagre otoliths (sagitta) and allows the simultaneous estimation of original body size and minimum number of individuals (MNI) from archaeological bone structures. We selected the following measurements to predict meagre body size: greatest dorso-ventral height, greatest mediolateral breadth, and greatest anteroposterior length of the vertebrae centra; maximum anteroposterior length, medial anteroposterior length, and dorso-ventral height of the sagitta. Our results show that the original body size of meagre can be accurately predicted from many bone measurements (r² range: 0.921–0.992). We exemplify the use of the regressions in the assessment of size variation and MNI of meagre from four Portuguese Mesolithic sites. We show that regression results provide additional insight into the significant role that this fish played in the subsistence of coastal fisher-hunter-gatherers, who targeted medium-sized animals but were also capable of acquiring rather larger specimens.     

Observed and calculated F2 peak heights and derived meridional winds at mid-latitudes over a full solar cycle

The peak height of the F2 layer, hmF2, has been calculated using the ‘servo’ model of Rishbeth et al. [(1978), J. atmos. terr. Phys. 40, 767], combined with the hedin et al. [(1988), J. geophys. Res. 93, 9959] neutral wind model. The results are compared with observed values at noon and midnight derived from ionosonde measurements at two mid-latitude stations, Boulder and Wallops Island, over a full solar cycle. The reduced height of the F2 layer, zmF2, is also computed for the same period using the observed hmF2 values and the MSIS-86 model. Day-night, seasonal, and solar cycle variations in zmF2 are attributed to neutral composition changes and winds. Anomalously low values of hmF2 and zmF2 during summer both at solar minimum and during the solar cycle maximum in magnetic activity may be associated with increases in the molecular to atomic ion concentration ratio. Under these circumstances the F2 peak may lie significantly below the O⁺ peak height calculated by the servo model. Neutral meridional winds at Wallops Island are derived from the servo model using the observed hmF2 values and the calculated O⁺ ‘balance height’. It is shown that if the anomalously low hmF2 values are used, unrealistically large poleward winds are derived, which are inconsistent with both theory and observations made using other techniques. For most conditions the F2 peak is clearly an O⁺ peak, and daily mean winds at hmF2 derived from the servo model are consistent with the hedin et al. (1988) wind model. Unexpectedly, the results do not show an abrupt transition in the thermospheric circulation at the equinoxes. Diurnal curves of the servo model winds reveal a larger day-night difference at solar minimum than at solar maximum.     

Plant microfossils in prehistoric archaeological deposits from Yuku rock shelter,Western Highlands,Papua New Guinea

Plant microfossil analysis was carried out on anthropogenic deposits from Yuku rock shelter, possibly occupied from before 14,200 cal. BP to recent times, in the Papua New Guinea Highlands. Elaeocarpus pollen has extremely high percentages throughout. Starch residues of lesser yam (Dioscorea esculenta) and one or more, undifferentiated Dioscorea species were identified, suggesting processing of these taxa since first use of the site. The latter include Dioscorea alata, Dioscorea bulbifera, Dioscorea nummularia and Dioscorea pentaphylla. Pollen and phytoliths of banana (Musa) appear 5200 cal. BP. We cannot differentiate between naturally growing and cultivated yams and bananas. Putative truffle (hypogeous Ascomycotina) spores in the deposits suggest foraging of truffles.     

8500-year-old Late Mesolithic garment embroidery from Vlasac (Serbia): Technological,use-wear and residue analyses

This paper presents results of contextual, technological, use-wear and residue analyses of body ornaments from two Late Mesolithic burials recently excavated at the site of Vlasac in the Danube Gorges of the central Balkans. Common to both burials are ornaments made from modified and unmodified carp (Cyprinidae sp.) pharyngeal ‘teeth’ along with Cyclope neritea marine gastropods. Experimental and low and high magnification use-wear approaches have been employed in reconstructing the way these ornaments were made and used. The precise contextual distribution of these ornaments has been recorded for the first time. The two examined burials exhibit a number of similarities, particularly in the way ornaments were placed in relation to the body. Both burials are also contemporaneous, dated to the mid-7th millennium BC. Implications of these findings for Mesolithic foragers' corporeal symbolism, group identity and regional and long-distance acquisition networks are briefly examined.