1901 ENTOMOLOGICAL SOCIETY. 37 



The Chairman of the Section made interesting reports upon his trips to the locations above 

 named. For the first time the Corniferous strata has been made a special study, being fully ex- 

 posed by operations having in view the drainage of lands adjacent to Mud Creek, which empties 

 into the Sauble, near Poit Frank. Fine specimens of Orthoceras from two to three feet in 

 length were found, many being broken by explosives used in blasting away the rock. A very 

 perfect specimen, one foot long, was shown to the class. Spirifers of larger size (Spirifer 

 striatus) were found very abundantly in beds of clay above this formation, also a number ( i 

 other fossils, Murchisonia being the chief. 



Because of the great excess of silica the use of the rock is very much restricted, being too 

 hard and too fragile and also containing iron, which makes it un-suitable for building purposes. 

 This is in decided contrast to the form it ion exposed at St. Mary's, where the Corniferous is re- 

 markably free from silica and contains an abundance of fossils of the Devonian Period and 

 < locasioually the remains of fossil fishes are found. 



The Hamilton formation immediately overlies the Corniferous at Arkona, where it is ex- 

 posed by the Sauble River. This vicinity is well known as one of the finest collecting grounds 

 in the world. Mnny distinguished scientists have visited the Sauble Valley, amongst others 

 Prof. Hall, New York ; Prof. VVinchell, Ann Arbor, and many others Geologists of lesser note. 

 Here trilobites abound, the characteristic species be"ng Phacops Bufo. Fossil corals, also of 

 great beauty and variety, completely silicified, are found here and Crinoids in vast abundance. 



In visiting this section a geologist may leave his hammer at home and come provided only 

 with baskets or an express wagon which he would have no difficulty in filling with these ai c ent 

 fossil remaing. Specimens from this district have been shipped to many museums in Great 

 Britain and United States. The Academy of Natural Science in Philadelphia was this year pre- 

 sented with a small collection of local specimens by the Chairman of the Section who thus adver- 

 tises Ontario in an efficient way. When our city sees fit to establish a museum we have at oar 

 doors a rich field in which to secure a very varied collection suitable for studying the Paleontology 

 of this district and which also may be used for exchanges. 



After being Chairman of the Geological Section since its inception, excepting one year 

 when Professor Andr-is occupied it, Dv. Wo dverton has now resigned in favor of Mr. Kirk, a 

 capable and energetic member of our section. 



The following reports will be placed in the hands of the Editor : 



Roads and Road-making ... .Mr. Kirk. 



The Gait Dolomites Mr. Goodburne. 



Methods < f Concentrating Gold • Mr. J. G. Smith. 



The Mastodon of Mount Bryd^e.-^ Mr. J. G. Smith. 



[The report on " Roads and Ruad-making " has already been published elsewhere.] 



Thk Galt Dolomites. 



Limestone is perhaps one of the most abundant of all minerals, and the most widely distri- 

 buted, quartz alone excepted. It appears in very many difl'erent forms, the ordinary one of 

 limestone being best known, with marble as the most valuable, and these two show the ex- 

 tremes of the substance — one the original material and the other the metamorphic condition. 

 Limestone is composed of carbonic acid, 44 ; lime, 56 ; but carbonate of iron or magnesia may 

 take the place of a portion of the carbonate of lime. A very large amount of our limestones, 

 . however, are properly dolomites, which differ from the limestone in the process of deposition, 

 and in chemical structure. Dolomite consists of carbonate of lime, 54.35 ; carbonate of 

 magnesia, 45 65; these including a small portion of protoxide of iron (leO) or magnesia. 

 Do'omitea are calcareous, and appear to have been simple chemical precipitates, and in some 

 cases to have originated from the alteration of limestone rocks by magnesia salts. 



