b BULLETIN OF IHE NATURAL HISTORY SOCIETY. 



stones and perched boulders observed in this district, as curious 

 objects of much interest. In this district also he found deep 

 fissures in the granite, and supposes that there have l)een violent 

 earthquakes and volcanic explosions, which had rent the rocks 

 asunder and thrown these boulders to the tops of the highest hills. 



This primar}' district of Dr. Gesner corresponds to the quartz- 

 rock and slate district of Messrs. Jackson and Alger, V)ut the 

 boundaries given by Gesner are more natural than those of the 

 Boston authors. Also it corresponds to the Lower Silurian of 

 8ir Wm. Dawson's map* but is much narrower. 



In his account of the second, or CJay slate district, Dr. Ges- 

 ner, while remarking upon the occurrence of granite, gneiss 

 and mica schist in this district, found it to contain also gray- 

 wacke and the " old mountain limestone " with remains of marine 

 animals and plants. The boundaries of this district as given by 

 Gesner nearly correspond with those of the " Transition " clay 

 slate of Messrs. Jackson and Alger, but where they differ 

 Gesner's boundaries are more correct and natural. 



Gesner's description of the iron ores of Clements and Nictau 

 also agree very nearly with that of the authors above named, and 

 l)Oth also describe in somewhat similar terms the fine Cjuartz 

 crystals of Paradise river and the bog iron ore of Aylesford. 



There is a difference in condition between the iron ores of 

 Clements and ISJ^ictau, for while the former ai'e converted into 

 magnetite, the latter are still hematitic ores. The Boston chem- 

 ists thought the alteration of the Clements ore due to heat from 

 the mass of trap in the North Mountains on the opposite side of 

 the Annapolis valley; Gesner on the contrary attributed it to the 

 vicinity of intr'usive granite. 



An interesting account is given by Dr. Gesner of the discovery 

 of a fossil of the zoophyte family! and of dendritic markings in 

 the grey slates at Beech ]Iill in Horton. Fossils (encrinitesand 

 triloljites) were also disco\ered in the clay slate formation at New 

 Canaan. Several pages are devoted to a description of the iron 



•■In Acadian Geology. 2nd Ed. London 1868. 

 t Now known as Dictyonema Websteri. 



