508 Annals of the Carne(;ie Museum. 



Contact with Other Formations. 



At various places throughout the Lake Champlain Valley the con- 

 tacts of the Chazy with the Beekmantown and Lowville formations 

 are exposed. When the Beekmantown -Chazy contact is shown, the 

 upper layers of the Beekmantown are a rather pure dolomite, and the 

 lower layers of the Chazy, which are a dense sandstone or quartzite, 

 lie conformably upon them. .At Crown Point, however, the surface of 

 the upper layer of the Beekmantown is irregular and the sandstone of 

 the Chazy fills the depressions in this layer, indicating either an inter- 

 val of erosion or underground solution. It is probably the former, as 

 will be seen later. 



The lower layers of the Chazy are the same throughout the Cham- 

 plain Valley, as the sandstones at the base are present at Larabee's 

 Point, Crown Point, Valcour Island, South Hero, Isle La Motte and 

 probably at Montreal (Logan). 



The contact with the Lowville limestone is not so well shown in any 

 section. Brainerd and Seely state that the highest layer of the Chazy 

 is a two-foot bed of sandstone. This sandstone is well exposed at 

 Crown Point, but as the writer has previously shown,'* it is overlain 

 by a layer of sandy limestone which contains Middle Chazy fossils. 

 At Valcour Island the sandstone is not exposed at ordinarily low 

 water, but that such a sandstone does occur is shown by the fact that 

 fragments of sandstone are found upon the shore just south of the ex- 

 posure of Lowville and Black River limestones. 



The Ottawa Valley Region. 



The Chazy of this region has been described in detail by Sir 

 William Logan, Ells, and Ami, of the Canadian Geological Survey. It 

 is not more than 200 feet in thickness, usually less, and is divided into 

 two parts, the lower embracing shales and sandstones, and the upper, 

 limestones. In certain sections there are about 20 feet of transition 

 beds in the middle of the formation, where the limestones are inter- 

 stratified with the shaly portion. 



At Greeces Point, on the Grenville canal, the contact between the 

 Calciferous and Chazy can be well seen. Here the dolomitic lime- 

 stones of the former are overlain by several feet of fine conglomerate 

 or coarse grit. This coarse grit soon graduates into greenish shale and 



^* Bulletin of American Paleontology, Number 14, page 20. 



