53^ 



NATURE 



[Al'RIL 6, 1905 



levels g-ive an idea of the height of the hills, so with 

 the Ordnance map azimuths, read to 1°, the dates 

 •of the use of the great and S.W. circU's arc approxi- 

 mately as under : — 



Great Circle 

 S.W. Circle 



1260 

 1075 



We seem, then, to have made a step in advance. 

 More accurate readings of the Ordnance maps and 

 accurate determination of the heights of hills may 

 vary the above values slightly. But that is an un- 

 important detail if it can be shown that we have a 

 new method of dating what went on in prehistoric 

 Britain at the time when the Athenians were building 

 the Hecatompedon. 



.•\ great amount of local theodolite work has to be 

 ■done, for while Mr. Lukis only referred to two out- 

 standing stones at the Hurlers,' there are many more 

 marked on the Ordnance map ; there are also others 

 besides the " quoit " at Stanton Drew. 



I am more rejoiced than I can 

 say to know that this local work 

 has already been begun under 

 the best possible conditions. As 

 it was impossible for me to leave 

 London when the significance of 

 the alignments was made out, I 

 appealed to the authorities of 

 University College, Bristol, and 

 of the Royal Cornwall Poly- 

 technic Society for aid. The 

 principal of the college. Prof. 

 Lloyd Morgan, together with 

 Prof. Morrow and his engineer- 

 ing class, have already made 

 observations at Stanton" Drew, 

 and Captain J. S. Henderson, of 

 Falmouth, an accomplished sur- 

 veyor, sent me last week from 

 the Hurlers the angular heights 

 along some of the alignments, 

 the means of eight readings ob- 

 tained with a 6-inch theodolite, 

 both verniers and reversed tele- 

 scopes being employed. Other 

 students of science besides my- 

 self will, I am sure, feel their 

 indebtedness for such opportune 



help. NORM.^N LOCKYER. 



parative rapidity of their formation, as shown by the 

 fact that " some of these isolated stacks of con- 

 glomerate are capped by boulder clay, and their 

 capitals may here and there be seen to have retained 

 their covering of thick peaty soil." 



The photograph of the tower of Eccles Church, an 

 object made so familiar by Lyell's " Principles," is 

 the last that was taken (in 1SS6), and the last that will 

 be taken, for the tower itself was destroyed in 1895. 

 Prof. Reynolds's photograph of the great Axmouth 

 landslip gives a good view of the " mighty chasm 

 which separated the foundering mass from the land." 

 The original describers of this were Buckland and 

 Conybeare, and a water-colour copy by Ruskin of Mrs. 

 Buckland's drawing still hangs in the I'niversity 

 Museum at Oxford. Of queer forms the " Rock and 

 Spindle," St. Andrews, Fifeshire, photographed by Mr. 

 G. Bingley and described by Prof. Bonney, and " Lot's 

 ^^'ife," Marsden, Durham, a "breccia gash " trans- 

 formed into a sea-stack, described bv Prof. Lr-bMur. are 



I 



BRITISH ASSOCIATION GEOLOGICAL 

 PHOTOGRAPHS. 



'X'HE _geological_ photographs committee of the 

 -"■ British Association and its indefatigable secre- 

 tary. Prof. W. W. Watts, are to be congratulated 

 on the third issue, which completes the first series, of 

 their admirable photographs. There are twenty-four 

 photographs in this issue, all of great interest, showing 

 much skill in technique, and considerable artistic power 

 in the choice of the point of view from which the 

 objects were taken. They treat of a variety of sub- 

 jects, chiefly the action of wind and rain, frost and 

 ice, and sea-waves, igneous intrusion, the character of 

 sedimentary rocks, and structures due to faulting and 

 folding. 



There are two good pictures of the remarkable rain- 

 eroded pillars of Old I^ed Conglomerate which occur at 

 .'Vllt Dearg, on the Spey, Morayshire, and remind us 

 of the similar forms which may be seen in much 

 younger deposits on the right side of the Brenner as 

 we travel towards Italy. They \yere first figured by 

 Sir .Archibald Geikic, who provides a description to the 

 photographs, in which he directs attention to the coni- 

 NO. 1849, VOL. 71] 



esiing on lerraucu gianiic suiiauc, .w. i- fl 



Photographed by Prof. H. E. .^iniMi : u. F,R 



among the quaintest; they would be good puzzles to 

 set a student in examination. The most novel subject 

 is the wind-worn surface of granite disclosed beneath 

 the Keupcr marl in the MouiUsorrel quarry, one of the 

 several proofs discovered by Prof. Watts of the desert 

 conditions which prevailed in these islands and else- 

 where during a part of the Trias period. We have 

 selected this for reproduction. 



.As this is the last issue of the first series it is use- 

 fully accompanied by some introductory letterpress, 

 which includes the names of the committee, a preface, 

 table of contents, and other information. We learn 

 from the preface that the idea of forming a systematic 

 collection of geological photographs originated with 

 Mr. Osmond W. Jeffs in iSSq"; to carry it out a com- 

 mittee of the British .\ssociation was appointed in iSqo, 

 and Mr. Jeffs acted as secnlary until 1S96, by which 

 time 141 2 photographs had been contributed. In 1895 

 Prof. W. W. Watts became secretary, and by iqo3 the 

 collection had grown to the magnificent total of 3754. 

 It is housed in the Museum of Practical Geology, 28 

 Jermvn-streel, S.W. The series issued to subscribers 

 and just completed consists of a selected number (72) 

 of these photographs, taken from negatives generously 

 lent by their owners, and furnished with descriptions 

 by many of the leading geologists of the day. 



