BUFFALO SOCIETY OF NATURAL SCIENCES IOI 



conglomerate to the north, south or west, the only possible one being 

 to the southeast where lay the old land of Appalachia. This is also 

 indicated with great certainty by the shape of the cone of this forma- 

 tion which is thickest in the southeast, thinning out to the north, 

 west and south. The material of this alluvia] cone could only have 

 been transported by rivers and its river-borne character and deposi- 

 tion upon land are well shown in the frequent occurrence of the tor- 

 rential type of cross-bedding, and in the absence of any typical marine 

 organisms, such as would be found in the subaqueous portion of a 

 delta. Apparently there was no sea-border portion of this deposit, 

 unless the Pittsford shale is considered as such. The Shawangunk 

 conglomerates found in Pennsylvania and New York, thin away 

 towards the region of Pittsford shale deposition, but actual connec- 

 tion has not been traced. There can, however, be little doubt that 

 the Pittsford shale represents the finest material brought by the 

 Shawangunk river from Appalachia. This mud was deposited very 

 near the sea border, but there is no evidence that it was deposited in 

 the sea, since the typical marine organisms are absent. It may be 

 that the influx of fresh water was sufficient to keep these out. Inter- 

 fingering with the shale, are the dolomite beds, deposited during short 

 incursions of the sea (see section 4). If we could trace these Pitts- 

 ford shales to the northern part of the state or into Canada, we would 

 expect to find them grading into pure marine limestones, but no out- 

 crops are accessible. The black shales intercalated between the con- 

 glomerate beds of the Shawangunk at Otisville and elsewhere repre- 

 sent the muds carried down by the river during times of flood. If 

 the eurypterids were living in those rivers, their exoskeletons would 

 have been floated down, while dead and even living individuals would 

 have been swept down by the force of the torrential floods. The 

 exoskeletons and floating bodies would settle down with the mud 

 on the drying up of the water from the flooded areas. That such 

 drying occurred is indicated by the presence of mud-cracks in these 

 intercalated shales. When this mud dried up and became cracked, 

 the eurypterid exoskeletons would be broken up and blown about by 

 the wind, until the fragments should be covered by the next torrential 

 deposit. This breaking up of the tests as the mud dried would 

 account for the fact that the larger eurypterids are always found in 

 a fragmentary condition, while the smaller ones are found whole. 

 How to account for this fact on any other hypothesis is difficult to 



