318 ANNUAL REPORT SMITHSONIAN INSTITUTION, 195 7 



Allowing for the possibility of burial of artifacts below sediments 

 with which they were contemporary, the evidence from the Shapwick 

 Heath pollen sequence indicates that clearing of the local forest was 

 begun toward the end of the Bronze Age and just before the construc- 

 tion of the Westhay trackway. A later and more pronounced maxi- 

 mum of weed and cereal pollen in sediments of late Iron Age suggests 

 that clearing and agriculture probably reached a peak of activity at 

 that time. The occurrence of barley grain in the ruins of a local 

 village of late Iron Age confirms the fact that agriculture was prac- 

 ticed during that era. 



The archeological record of Shapwick Heath history ends with 

 the Eomano-British artifacts which are datable to the time of the 

 dissolution of Roman power in Britain at the close of the fourth 

 century A. D. 



Pollen data from a peat bog near Northford, Conn., illustrate 

 how fossil tree pollen can be useful in inferring the nature of pre- 

 historic climate. In the pollen diagram (fig. 6), from this bog, tree- 

 pollen curves plotted on the left include data for spruce (Picea) , a 

 genus that no longer grows in appreciable numbers in the State. 

 During the deposition of zone A, which began some 13,000 years ago, 

 spruce was the dominant pollen type, and therefore was probably 

 the dominant tree in the local forests at that time. By comparison of 

 the amount of spruce in zone A sediments with its density in pollen 

 rain of areas to the north, one finds that the nearest comparable mod- 

 ern concentration of spruce lies in the Maritime Provinces of southern 

 Canada. Because spruce distribution and abundance are controlled 

 by growing-season temperatures, one can make the definite conclusion 

 that July temperatures of southern Connecticut during the deposition 

 of zone A were at least as low as those now found in the Maritime 

 Provinces. These temperatures average 16-18 °C. in July and are 

 3 to 4 degrees cooler than those now typical of southern Connecticut 

 in the month of July (Leopold, 1957) . 



If their present ecology is well understood, microalgae or marginal 

 water plants in the fossil assemblages are sometimes helpful in re- 

 vealing the original hardness or salinity of the water. In the Totoket 

 diagram of figure 6, water plants and algae, shown on the far right, 

 include : char a and Myriophyllum (water milfoil) , now characteristic 

 of mineral-rich lakes; Pediastrum, a small floating alga that now 

 prefers open water; and the marginal water plants Typha (cattail) 

 and Nymphaea (yellow water lily). Remains of all these are espe- 

 cially prevalent in sediments of zone A. One can therefore infer 

 that during deposition of zone A when the forests of southern Con- 

 necticut were predominantly spruce, this basin was a lake with waters 



