ABSTRACTS OF PAPERS 133 



south of Crown Point station) from wliicli they liave been collected in the 

 Champlain area. 



Comparisons have been made of specimens of the Pleistocene species of the 

 Champlain area with those of Canada and with recent representatives, and it 

 has been found that the Champlain fauna is a dwarf fauna. 



The Pleistocene fauna of the Hudson Valley is briefly considered. No fossils 

 have been reported from these Pleistocene deposits south of Croton Point, 

 either from the New York or New Jersey shores. The most northern point at 

 which Pleistocene fossils have been reported from the Hudson Valley is at 

 Storm King, 50 miles above New York, where was found, in drilling a series 

 of holes across the Hudson bed, a fauna represented by two species living at 

 present along the New England and New Jersey coasts, Mulinia lateralis and 

 Trivia trivittata. This has been shown by Shimer to be a dwarf fauna. At 

 Croton Point, about 20 miles farther south, occurs a lacge Pleistocene oyster 

 bed in which are found the following marine forms : Mya arenaria, Modiola 

 demissMS, Mulinia lateralis, and Alectrion (= Nassa) obsoleta. The largest 

 specimen of Mulinia lateralis here is larger than the large specimens from 

 Storm King, but smaller than the recent shore forms, as one might expect in 

 waters of decreasing salinity. Salt-water organisms at present pass up the 

 Hudson only to the Highlands, though its waters are brackish as far north as 

 Poughkeepsie. 



The data for the Hudson Valley Pleistocene fauna are meager, but the evi- 

 dence obtained, however, seems to lead to conclusions similar to those arrived 

 at for the Champlain area. The waters of the Pleistocene Hudson estuary 

 were so freshened going northward that (1) only a few marine forms were 

 able to advance into these waters at all; (2) so far as present knowledge goes, 

 only two species reached as far up as Storm King, 50 miles above New York, 

 and none have been reported north of this locality; (3) the two species found 

 at Storm King represent a dwarf fauna, one of them, Mulinia lateralis, occur- 

 ring in a dwarfed condition (less so, however) at Croton Point, about 20 miles 

 farther south. 



It is recognized that clay deposited in fresh water shows a laminated char- 

 acter not found in similar deposits in very brackish or salt water. The lami- 

 nated character of the Hudson ^'alley clays, seen as far south as Haverstraw, 

 and the absence of this peculiar laminated character in any of the localities 

 in the Champlain area where marine fossils were found verifies what has al- 

 ready been indicated by the distribution and character of the faunas of these 

 areas: (1) that the Pleistocene waters of the Hudson Valley were fresh or 

 practically fresh north of Storm King; (2) that the Champlain Sea extended 

 southward in a brackish condition, gradually freshened to a point a few miles 

 south of Crown Point station, and that south of this area its waters were 

 fresh or practically fresh. 



At 5.30 the Society adjourned until the following da}^ 



Wednesday evening at 7 o'clock the members attended the annual din- 

 ner of the Geological Society of America and alfiliated societies, at the 

 Chicao;o Beach Hotel. 



