Transactions. 87 



The underlying strata over a wide area round Dumfries is 

 Permian Breccia, covered over with boulder clay of a somewhat 

 friable nature. The Breccia stands out at Cluden !Mills, the Craigs, 

 and other places. All are familiar with the Permian sandstone of 

 Locharbriggs and other quarries in the county, but from the soft 

 character of the stone, it does not retain marks of glaciation at 

 exjjosed places so well as harder rocks. 



A striking feature of the locality, as of nearly the whole of 

 the Scottish Lowlands, is the rolling character of the country ; the 

 green knolls, and rampart -looking ridges usually called " kames," 

 composed of stones of all sizes, gravel, and sand. It is admitted 

 that these mounds cannot be clearly accounted for, but Professor 

 James Geikie is of opinion that they point to abundant streams of 

 running water discharged across the country from tlie rapid melt- 

 ing of snow and ice, to a " pluvial period," or after the Ice Age 

 " Great Thaw " spoken of by Sir Charles Lyall. 



N.B. — It maj- be noticed here, that Dr Croll and others, who 

 have made calculations for the eccentricities of the orbit of the 

 earth and other planets, used Leverrier's Formula in making their 

 calculations. In conversation with Dr Young, Professor of Geology 

 in the University of Glasgow, he hinted to me that the formula 

 was not reliable. If this were true, it is obvious that the conclu- 

 sions as to the last period of high eccentricity might be erroneous. 

 In these circumstances I thought it would be well to make enquiry 

 at the highest authority whether the formula was reliable or not. 

 Dr Chinnock very kindly, in the interests of the Society, and on 

 my own account, wrote to the Astronomer Royal making the 

 enquiry. The courteous reply received from Greenwich Observar 

 tory is herewith given in full. It will be seen that Leverrier's 

 Fonnula cannot be considered unreliable for the last Glacial Epoch, 

 which is all that we have under consideration. "When every 

 allowance is made it does not appear that the period covered by 

 the epoch, as calculated by Dr Croll and others, can be very far 

 out. 



J. W. 

 Royal Observatory, Greenwich, 



London, S.E., 1890, Sept. 19. 

 Dr E. J. Chinnock, 

 Dear Sir, 



Leverrier's Formula for the eccentricities 

 of the orbit of the earth and other planets have been computed with 

 great care, but the calculations are rather comj>licated, and independ- 



