Notices of Memoirs — Nova Scot ian Geology. 569 



Mountains by officers of the United States Geological Survey. It 

 consists of calcareous columns with convex layers. Three localities 

 are known where it has been found, and in a plate accompanying the 

 paper its structural characters are exhibited. 



5. — A New Gtenits and a New Species of Silurian Fish. By 

 Gr. F, Matthew, LL.D., etc. Trans. Eoy. Soc. Can., Third Series, 

 vol. i, sec. iv, p. 7. 



THIS is a description of an ancient and interesting type of fish of 

 early Silurian age. The form is related to Phaneropleuron, 

 from which it differs in the arrangement of the fins, etc. It is from 

 strata in King's County, New Brunswick, Canada. 



6. — The Physical Evolution of Acadia. Part I : The Insulak 

 Stage, etc. By G. F. Matthew. Bull. Nat. Hist. Soc. of New 

 Brunswick, 1907, vol. vi, p. 3. 



IN this article the bearing of the geological changes which occurred 

 in the maritime provinces of Canada prior to Devonian time is 

 shown. The history is divided into several periods by the physical 

 revolutions that occuiTed. The first period (called the Laurentian 

 phase) is marked by the occurrence especially in Southern New 

 Brunswick and in Cape Breton of abundant limestones, which are 

 compared to the Granville limestones of the Ottawa valley. 



The second great period (Huronian phase) is marked in Nova Scotia 

 by the enormous deposits of the gold-bearing series of that province, 

 and is compared to clay slates, chloritic slates, and other rocks in 

 Southern New Brunswick, which are thought to be a deep-water 

 representation of the gold-bearing series of Nova Scotia. 



The third great period of deposition of sediments is marked by the 

 widespread Cambrian deposits of the Atlantic region of Canada, which 

 are best shown in Southern New Brunswick and Cape Breton Island 

 in Nova Scotia. This great series in both provinces runs up into and 

 includes the lower part of the Ordovician. 



This series is followed by an important geological hiatus, the upper 

 Ordovician being absent from all this region, and the first rocks 

 which succeed the Cambrian series are of the age of the Ludlow or 

 thereabouts. This is the Silurian phase, and extends upward to 

 include the base of the Devonian (if the Upper Helderburg formation 

 be regarded as such). 



Up to this time in its geological history Acadia when submerged 

 in part was insular, or divided from the rest of the American 

 continent by one or more sounds, extending from the present Gulf of 

 St. Lawrence to the Gulf of Maine, and further inland in New 

 England. Southern Acadia up to this time was dominated by insular 

 conditions, and for most of the time prior to the Devonian age was 

 an island cut off from the mainland of America. 



Two maps are given to illustrate this history, one showing the 

 conditions in the middle Lower Huronian time, and the other drawn 

 to show its aspect in Upper Silurian time (Clinton to Niagara). 



