﻿Geology and Mineralogy. 243 



fishes and molluscs, some of which are of Eocene types, according 

 to Cope and Whiteaves, and its flora is akin to that of the upper 

 Cretaceous. The upper Laramie has offered a flora so modern in 

 aspect that it has even been regarded as Miocene, though in re- 

 ality not later in age than the Eocene. The Willow Creek or 

 middle Laramie division may therefore (as suggested by the au- 

 thor in his memoir of last year on the western Cretaceous) be 

 regarded as the transition from the Cretaceous to the Eocene. 



The question of the correlation of the Laramie with other for- 

 mations has been much complicated by the reference, in the 

 United States and elsewhere, of beds holding its flora to the Mio- 

 cene period, and these difficulties cannot as yet be wholly over- 

 come, though they are gradully being removed. In Canada, since 

 the plants began to be collected and studied there has been little 

 doubt on the subject, and the author now, as heretofore, holds to 

 the correlation with the Laramie flora of the so-called Miocene of 

 Mackenzie River, Alaska, Greenland and Spitzbergen, and be- 

 lieves that they should be regarded as not newer than Eocene. 



The greater part of the paper is occupied with the description 

 of the fossil plants of the formation, including those collected in 

 the Eastern area by Dr. Selwyn and Dr. G. M. Dawson, and those 

 obtained from the Western area by the latter, Mr. Weston, Mr. 

 Tyrrell and the author. These include a large number of exo- 

 genous trees, all belonging to modern genera, as Platanus, Cory- 

 lus, Populus, Salix, Viburnum, Carya, Juglans, etc. There are 

 also some curious plants allied to the modern trapa or water chest- 

 nut, and coniferous trees of the genera Taxodium, Sequoia and 

 Salisburia, as well as some ferns and equisetaceous plants of 

 much interest, more especially in reference to their geological 

 and geographical distribution. — Abstract of Paper read to Royal 

 Society of Canada, May, 1886. 



11. On the Decay of Building Stones ; by T. Eglestow (Am. 

 Soc. Civ. Eng., xv, 1886). — In this paper the writer reviews some 

 of the causes of decay affecting building stones, especially such 

 as depend on the removal of an ingredient by solution or decom- 

 position. Many facts of interest are reported. Among the obser- 

 vations he mentions that dolomitic limestones, which in many 

 regions crumble to sand, in the case of monuments as well as in 

 those of the native ledges, owe this to the fact that they are to a 

 large extent mixtures of true dolomite and limestone; and that 

 the limestone, the most soluble portion, is dissolved and removed 

 by percolating carbonated waters. 



12. Geological Studies, or Elements of Geology for High 

 Schools, Colleges, Normal and other Schools; by Alexander 

 Winchell, LL.D. 514 pp. 12mo, with 367 illustrations. Chicago, 

 1886. (S. C. Griggs & Co.)— In this work Professor Winchell 

 shows the hand alike of an instructor, a thinker, and a field- 

 observer. He introduces the student to the subject by presenting 

 first a chapter on the drift and some other phenomena over the 

 earth's surface open to ordinary observation, sometimes considered 



