The following notes have been made during a few weeks' holiday in the Isle of Man, and my special object is to notice those points which have a bearing upon the geology and physical history of the neighbouring Cumberland mountains. For many years I have, from time to time, looked across to the hills of Mona's Isle, regarding them as a portion of the Cumbrian group standing aloof from their brethren, and often have I wished to carry my hammer amongst them. My wish has at last been fulfilled, but the bad weather of the coldest of summers has prevented the observations made being as full as I had intended. Such as they are I offer them.

Dr. Croll's “Climate and Time” is perhaps the most important geological work that has appeared in recent years, certainly the most valuable and original that refers to Glacial Geology. It teems with novel and instructive ideas. The part which is best known and has chiefly contributed to its celebrity is the theory, propounded and maintained in the first four chapters, of the causes of the Glacial Epoch. Though the theory met with much opposition at first, it seems now to be gradually gaining belief. Not only are Dr. Croll's views accepted by geologists, but his arguments are quoted in text-books. Now, when Science is used as a means of education, it is of high importance that the reasoning placed before the student should be sound. I propose in this article to examine Dr. Croll's description of the manner in which, according to his views, Glacial Periods have been brought about, to discuss the soundness of his reasoning, and to investigate the actions of the causes which he suggests. Some of the remarks here made are probably originally derived from an able article by Mr. S. V. Wood, jun., in the Geol. Mag. for 1876. The suggestion at the end of the paper is due to Mr. W. M. Hicks, M.A., Fellow of St. John's College.

The first part of the “Records of the Geological Survey of India” for 1879 contains some interesting notes by Mr. R. Lydekker, B.A., descriptive of a “few fragmentary bird-remains” recently obtained from the Tertiary deposits of the Siwaliks, and preserved in the Geological Museum at Calcutta. The subjects of most interest alluded to in this memoir are some bones referred to Dromœus, by Mr. Lydekker, and his remarks thereon, and upon some bones of kindred birds which form part of the extensive series of vertebrate remains collected in the same range of hills by the late Colonel Sir Proby T. Cautley, then Captain in the Bengal Artillery, and presented by him to the National Collection.

Since my former paper on the rocks of the Curlew and Fintona districts was published, I have had an opportunity of more carefully examining these districts. Both are eminently favourable for the theoretical geologist, as in them the rocks are much obscured by drift; however, for a careful and painstaking explorer, there are sufficient sections exposed, to show the geological age of the rocks. The accompanying diagram represents the rocks as they occur in the Curlew Mountains district.

In the present communication I propose to direct the attention of British Geologists to three most valuable memoirs recently published by Mr. G. Linnarsson, the eminent palæontologist of the Geological Survey of Sweden; and at the same time to point out, as briefly as may be, what appears to me to be their special bearing upon certain tentative or disputed points in British Geology. They treat of subjects of great interest to the student of the palæontogeology of the Lower Palæeozoic or Proterozoic Rocks; but are printed in the Swedish language, with which, unfortunately, few amongst us are familiar. The first two papers deal with the Graptolite-bearing rocks of Sweden; the third treats of the peculiar fauna of a recently-detected horizon in the prolific Paradoxidian or Primordial Zone.