168 
THE GEOLOGIST. 
the Lias having undergone the action of fire, and of that formation being the sepulch re 
of the Wealden Iguanodon : with these and other glaring instances of carelessness 
before us, we must say, that, far fi'om making it easy, it is, we think, making 
geology very hard for even a geologist to understand. Still a book of the 
sort this assumes to be is wanted, and the idea was good. Our sincere advice to 
the author is to get some competent Greologist to revise the facts, and to pay 
more attention to the grammatical rules and requirements of the English 
language, and then we can assure him he will find no one more ready than 
ourselves to promote the sale of his little book. But in justice to those readers 
who trust to our judgment and advice, we cannot recommend this edition. 
The Canadian Naturalist and Geologist. Vol. ii.. No. 4, Sept., 1857. 
This interesting number contains an account of the eleventh meeting of the 
American Association for the Advancement of Science. 
Papers were read before the section of Natural History and Geology, by Mr. 
Snell, "On the quantitative assay of chromium by the blow-pipe ;" by Prof. Dawson 
" On some curious flexures in the Broad-top coal-strata of Pennsylvania attributed 
to lateral pressure ;" and one by Sir. W. E. Logan " On the great series of Canadian 
metamorphosed rocks," which the author of this paper had named respectively the 
Huronian and Laurentian series of Canada. This is a paper worthy of perusal by 
those who take part in the present sub-silurian enquiry, and the tracing out of 
the remnants of that oldest world whose fragments are being found among the 
so-called azoic rocks, and driving that term bit by bit out of its geological territory. 
The Huronian rocks, according to Sir William, are often nearly vertical, and 
are disposed unconformably under the Silurian Formation, the lowest strata of 
which are made up of the debris of these unquestionably older rocks. 
Papers were also read by Mr. J. Sterry Hunt " On the origin of magnesian rocks ; " 
by Prof. G. H. Cook " On the subsidence of the land on the sea-coasts of New 
Jersey and the adjoining States;" and by Mr. Hunt "On the metamorphism cf sedi- 
mentary rocks." 
The two interesting letters on the crystalline rocks of the North Highlands of 
Scotland by our own eminent geologist. Sir R. L Murchison, with notes on 
their fossils by Mr. Salter, have made the Americans partially acquainted with 
the subject of Sir Roderick's last communication to the Geological Society on the 
metamorphism of the Scotch Silurian strata. 
Among the other valuable papers which our space will not permit us to 
notice at length, are those by Professor Silliman " On the dressing of metallic 
ores;'' Sir W. E. Logan "On the subdivision of the Laurentian rocks of 
Canada into two great groups characterized by the presence of much lime or by 
the comparative absence of that mineral compound ;" Prof. Chapman " On the deposi- 
tion of native metals in vein-fissures by electro-chemical agency, and on the 
saltness of the sea ;" Prof. Dawson " On newer pliocene fossils of the St. Lawrence 
Valley ;" Prof. Ramsay " On the succession of fossils in British rocks ;" Prof. Pierce 
" On the formation of continents ;" Prof. Guyot " On the physical geography of 
Africa;" Prof. Hall "On the direction of the currents of deposition and source 
of materials of the older Paleozoic rocks ;" and Prof. Swallow " On the geological 
survey of the Missouri, &c." Many of the papers in the other sections of the 
Association, and some of the extraneous articles in this number of the Magazine, 
are not without interest to the geologist. 
