Reviews — Penning' s Field Geology, 465 



recurrent period of cold, during the latter part of the Glacial 

 epoch. And it continued, in his opinion, to be formed while the 

 slopes remained exposed, and ceased only as vegetable matter began 

 to cover up the surface. 



The Eev. W. S. Symonds contributes some notes on the Geology 

 and Archasology of Malvern, having reference more especially to the 

 Permian and Triassic rocks. He observes that the pebble-beds 

 towards the base of the ' water-stones ' contain pebbles of a quartz- 

 rock, exactly similar to those of the famous Budleigh Salterton 

 Beds. 



Other papers there are on the Ancient Wall of Gloucester, on 

 Sherston Magna, on the Ancient Camps of Gloucestershire, and on 

 Offa's Dyke, but these do not come within the province of the 

 geologist. H. B. W. 



I^:E3A7"IE"v^^s. 



I. — Field Geology. By W. Henry Penning, F.G.S. With a 

 Section on PALiE ontology. By A. J. Jukes-Brownb, B.A., F.G.S. 



8vo. pp. 227. (London ; Bailliere, Tindall, & Cox.) 



AMONG the many species of Geologists whom the progress of 

 Science has developed, the Field Geologist is perhaps the 

 most peculiar in his life history and method of work. There is, it 

 is true, a kind of gradation between all classes of workers, but the 

 man who devotes his time to the mapping out of various strata 

 exposed at the surface has very generally been enveloped in a sort 

 of mystery. Many of those whose opportunities of going into the 

 field are confined to a month or six weeks in the year are at a loss 

 to understand the evidence by which the geological lines are drawn 

 upon our maps with such apparent precision, and if in their exami- 

 nation of fresh cuttings they find a boundary-line has been drawn 

 five or ten chains too far in one direction, or a small fault has been 

 altogether omitted in another, they are confirmed in their opinion 

 that mapping is to a great extent conjecture, and that the lines 

 depend very much upon the fertility of the imagination. But the 

 Field Geologist is no more a sudden and special creation than the 

 Lithologist, the Mineralogist, or the Palaeontologist. In each branch 

 of inquiry development can only result from experience, and although 

 many Geologists possess a wide range of knowledge that embraces 

 every branch of the science, the Field Geologist is more generally 

 restricted to his special work. And yet, with this restriction, they 

 may include among their number some of the most eminent of 

 Geologists, William Smith, Conybeare, Sedgwick, Murchison, and 

 De la Beche, — each gained his reputation from hard work in the 

 field. 



But the work of the Field Geologist of the past is to some extent 

 different to that of the present generation. The honoured leaders, 

 so far as our country is concerned, have drawn in all the main 

 outlines, and the work that they left to be done is but the filling in 

 of the details. The lines sketched in by William Smith, sometimes 



DECADE II. — VOL. III.— NO. X. 30 



