E. MINERALOGY AND GEOLOGY. 97 



dog or other sledges, provided the party start under experi- 

 enced guides, and sufficiently early in the year. 15 A, Au- 

 gust 19,1871,247. 



KEPOET ON THE GEOLOGY OF JAMAICA. 



A report on the geology of Jamaica, by Mr. James G. Saw- 

 kins, has recently been published by the British government, 

 and, in the interest attaching to the West Indies at the pres- 

 ent time, furnishes an important addition to our means of ob- 

 taining a thorough acquaintance with that region. The phys- 

 ical geology and the special structure of the island are given 

 in considerable detail in this work, which is accompanied by 

 a large map of the island, suitably colored to show the differ- 

 ent geological formations. Several appendices are given in 

 the volume, one of them being a complete classification of the 

 organic remains of the island, by Mr. Etheridge, who refers 

 them respectively to their equivalents in the cretaceous and 

 tertiary deposits of Europe. According to Sir Roderic Mur- 

 chison, the practical conclusions to be reached from the report 

 of Mr. Sawkins and the appendix of Mr. Etheridge are that, 

 in Jamaica, as in most of the West India islands, the princi- 

 pal geological deposits are almost exclusively of the miocene 

 age of the tertiary series, the only exceptions being in Trini- 

 dad and Jamaica, where eocene and cretaceous formations oc- 

 cur. Hence it follows that the igneous rocks which are asso- 

 ciated with such deposits are for the most part either of the 

 miocene age or posterior to that era, some of them, indeed, 

 having been recently erupted. 



SEA BOTTOM ALONG THE ATLANTIC COAST OF THE UNITED 



STATES. 



-A 



At a meeting of the Boston Society of Natural History a 

 communication was presented by Count Pourtales in reference 

 to the character of the sea bottom offthe coast of the United 

 States south of Cape Hatteras, and based upon the researches 

 of the Coast Surve} r . According to his statement, the princi- 

 pal constituent of the coast is silicious sand from the coast- 

 line to about the line of one hundred fathoms a limit which 

 coincides nearly with the inner edge of the Gulf Stream 

 throughout the greater part of its course. Outside of this 

 line is a whitish calcareous mud, containing globigerina, and 



E 



