Igneous Rocks. 67 



of St Lawrence, and near Quebec, Mr Lyell infers that the climate of 

 Canada was colder than now during the era immediately antecedent to 

 our own times. The shells, which were determined by Dr Beck, differ 

 in great part from those now living in the Gulf of St Lawrence, agree 

 more nearly with arctic genera and species, and resemble those which Mr 

 Lyell collected at Uddevalla, in Sweden ; whereas, if the living shells 

 most abundant in the Swedish and Canadian seas are contrasted, they 

 differ almost entirely. From notes sent by Capt. Bayfield, it appears 

 that, at different depths in the stratified sand and clay containing the fossil 

 shells, near Quebec, insulated boulders are numerous, which, it is pre- 

 sumed, have been brought down at distant intervals by drift ice, and have 

 dropped to the bottom of the sea as the ice melted. 



While Mr Lyell, by the aid of Dr Beck's determination of fossils, had 

 adopted these views respecting the climate of Canada, Mr James Smith 

 of Jordan Hill had been led by independent observations to a similar 

 conclusion respecting the climate of Scotland during the newer pliocene 

 era, arguing from the arctic character of the testacea found in the raised 

 beds of the valley of the Clyde, and other localities. In the first of two 

 papers communicated by this author, he regarded all the deposits abound- 

 ing in recent shells in Scotland and Ireland as belonging to one group ; 

 but in his second memoir he contends that there are two distinct forma- 

 tions on the Clyde, in the older of which there are from ten to fifteen per 

 cent, of extinct or unknown species of shells, which he refers to the 

 newer pliocene system of Lyell ; whereas all the species found in the 

 newer, which he calls post-tertiary, exist also in the present seas. Dur- 

 ing this post-tertiary period, which is considered to have been anterior 

 to the human epoch, an elevation of at least forty feet took place on the 

 shores of the Clyde. Mr Smith affirms that the till, or unstratified ac- 

 cumulation of clay and boulders, belongs not to the post-tertiary, but to 

 the older pliocene division. 



Igneous Rocks. — The principal communication we have received on 

 rocks of igneous origin has been from our secretary Mr W. I. Hamilton, 

 who lias read an interesting paper on the north-west part of Asia Minor, 

 from the Peninsula of Cyzicus to Koola, with a description of the Kata- 

 kekaumcnc. Between Cyzicus and Koola the principal stratified rocks 

 are schist, with saccharine marble, compact limestone resembling the 

 scaglia of Italy and Greece, tertiary sandstones, and tertiary limestones. 

 The igneous rocks are granite, pcperite, trachyte, and basalt. The ter- 

 tiary limestones are referred to the great lacustrine formation which occu- 

 pies so large a part of Asia Minor. Hot springs burst forth near Singerli 

 from a porphyritic trap-rock. The Katakekaumene is a volcanic region, 

 extending about seven miles from north to south, and from eighteen to 

 nineteen east and west. It presents two systems of volcanic craters and 

 coulees : the older of them arc placed on parallel ridges of gneiss anil 

 mica slate, and the newer in the intervening valleys ; hence he argues, 

 that, when the latter eruptions took place, the lines of least resistance to 



