Raymond: 'I'hk C'hazv Formation and its Fauna. r).")^ 



sandstone containing I.i)i:^til(i hraiinrdi (the most abundant species 

 in the basal zone at \'alcour Island), and extends to the top of the 

 section, a range of 276 feet. While the Crown Point fauna contains 

 the characteristic species of the second division at Valcour Island and 

 Chazy, not all the species found in these latter localities are found at 

 Crown Point. The Crown Point fauna does not, however, contain 

 any species which is characteristic of any other than the Moilurites 

 inagnus division. The Caiiiarota'chia plena fliuna is entirely absent, and 

 there is no fauna between the horizon with Liiign/a braiiierdi and the 

 horizon containing the Afacliiritcs iiiagmis fauna, the entire zone of 300 

 feet which occurs lietween these latter horizons at Valcour Island 

 being absent at Crown Point. These facts can have but one interpre- 

 tation, namely, that at Crown Point the invading Chazy sea did not 

 arrive until at least 300 feet of strata had been deposited in the region 

 of Chazy and Valcour Island. Further, that the basal sandstone at 

 Crown Point, cannot, therefore, hold the horizon of the one at the 

 base of the Valcour Island section, but is another one at least 300 feet 

 higher in the section and representing the shore conditions of the 

 invading sea. A peculiar feature of this sandstone is that it has the 

 Lingula brainei-di of the Valcour Island basal sandstone, but as none 

 of the other species of the Liiigtila braina-di faunule (see page 549) 

 are present in this bed at Crown Point the inference is that this species 

 is generally connected with the littoral, sandy habitat and follows the 

 invading shore conditions of the Chazy sea. This inference is in 

 keeping with the known habitat of some of the Lingulce of the present 

 day. The facts noted therefore lead to the conclusion that the sand- 

 stone seen at the base of the different sections of the Chazy formation 

 is not one horizon holding a definite place in the time scale, but that 

 it is a tangential sandstone marking the base of the invading sea. 



Comparison with Brainerd and Seely^ s Section at Crotvn Point. 



It will be noted that this interpretation of the Crown Point section 

 differs considerably from that of Brainerd and Seely. (See page 506 

 for their section.) 



They assign to their division A (Lower Chazy), the basal 48 feet, 

 of which 23 are sandstone. In their zone A^, 25 feet in thickness, the 

 present writer found, on collecting as large a number of species as 

 possible, that the faunule contains three of the characteristic specie^ 



