54 J^ew Puhlications. [Jan., 



slates and shales of a variety of colors, as red and brown of 

 various shades, together with dark colored slates in which the coal 

 seams are usually found. The rocks with which our readers will 

 be most familiar, are the gray and greenish-gray sandstones, which 

 are seen through all parts of the United States, in what are called 

 the Nova Scotia grindstones; most, if not all, are taken from car- 

 boniferous formations of this region. 



The whole thickness of the Nova Scotia coal measures, as de- 

 termined by Mr. Logan, is fourteen thousand Ave hundred and 

 seventy feet and eleven inches. We look w^ith great interest to 

 the completion of this survey. This being finished, we shall then 

 be in possession of the geology of so much of this continent as 

 is embraced in the area lying between the Gulf of the St. Law- 

 rence and the Gulf of Mexico, and from the Atlantic to the plains 

 which border the Rocky mountains. 



Such has been the spirit with which geology has been pursued 

 in this country, by American geologists principally, that those in 

 the oldest rank of observers remember when the first blow was 

 struck and when the first hammer was raised upon our rocks. 

 We groped in the dark nearly two-thirds of the time in which 

 geology has been pursued in this country. The most important 

 advance which has been made in this science, was achieved when 

 the geology of New- York was determined, and when the order 

 and arrangement of series was first exhibited. We then had, and 

 not till then, the key to North American geology. 



We do not, however, mean to be understood, that all has been 

 done even in New-York, so that nothing more remains; the lead- 

 ing parts and principles only are settled. We have the great 

 outlines of our geology laid out. What remains is the work of 

 filling up w^ith local details, which from their nature will result 

 some of the most important discoveries belonging to this depart- 

 ment of knowledo;e. 



