8 BULLETIN OF THE NATURAL HISTORY SOCIETY. 



ing the area about Woodstock, represented by Gesner simply as clay 

 slate or argilhtes, and differently marked from that of the similar belt 

 south of the granite, is by Robb, and correctly, made of the same age 

 as the latter. It is probable that in referring both of these great belts, 

 which are more or less metalliferous, to the Cambrian system, Gesner 

 and Robb were, upon the whole, more correct than the officers of the 

 Geological Survey so many years later. 



In Gesner's map a considerable belt of rock skirting the southern 

 seaboard from Passamaquoddy Bay to Chignecto Bay, and now known 

 to be Pre-Cambrian (Laurentian and Huronian), is referred to the 

 Lower Silurian, or its supposed equivalent, the Graywacke System. 

 This, undoubtedly the oldest group of rocks in the Province, and a 

 part of the Acadian protaxis, is by Robb made still younger, or Upper 

 .Silurian, possibly through the knowledge of the occurrence of Upper 

 Silurian shells in some of the areas, such as Passamaquoddy Bay, where 

 they are to some extent associated with and overlie the beds of the 

 older system ; or, the fact that such Upper Silurian rocks had been 

 shown by Jackson to occupy large areas along the coast of Maine, 

 rendered it probable that the apparent extension of these in New 

 Brunswick should be referable to the same horizon. The Upper 

 Silurian rocks of Northern New Brunswick, not indicated in the in- 

 complete map of Dr. Gesner, are by Dr. Robb clearly distinguished, 

 the lines representing its southern margin showing a somewhat close 

 approximation to their true position as determined by later investiga- 

 tion. On the north the border is made to exclude Temiscouata Lake, 

 of which the greater part is really bordered by Silurian strata. 



In this connection the following extract from a letter of Sir Wm. 

 Dawson to Mr. S. W. Kain, in answer to certain enquiries of the latter, 

 will be read with interest : 



As stuted in Acadian Geology, p. 502, the first fossil plant seen by me from 

 the Devonian of southern New Brunswick was a Calamite (('. i<i<li<tiiis Brongt. 

 C. transitionis Goept.), afterward illustrated by many specimens from the 

 vicinity of St. John. This specimen Dr. Robb brought to .Montreal. I think, 

 .it, the time of the meeting of the American Association herein 1857. At the 

 time these rocks near St. John were supposed to \»- Lower Silurian, and the 

 Calamite showed that there must be newer beds there, though it was a species 



not found in the eoal formation. I suggested at tin' time to \h\ Robb that QH 



his return he should endeavour to ascertain if other fossil plants were present, 

 and what portion of the slates and sandstone rocks near St. John contained 

 them. This he proposed to do, hut did not live to carry cut his intentions, and 

 the work fell into the hands of Messrs. Matthew and Haiti, by whom it was so 



-uceessfully carried out. I did nol know if Dr. Robb had any conference with 



