80 Reticles — Richardson^s Geology of Cheltenham. 



The present modes of dealing with geology are the outcome of 

 a gradual growth from the foundations laid by William Smith in 

 his " Strata identified by Organized Fossils " ; the more detailed 

 study of the succession of life-forms having been locally initiated 

 by Strickland, and followed in ever-increasing detail. While the 

 two schools may be said to be in active existence, there is no reason 

 whatever for any antagonism between them. The " older " may be 

 said to follow the broad outlines of Smith's grouping into strati- 

 graphical divisions or formations, such as can be represented on 

 geological maps ; formations which indicate certain physical con- 

 ditions, however local they may be, and the beginnings and endings 

 of which must have varied considerably in point of time. None 

 the less interesting are these formations and their fossils, their 

 stratigraphical changes and method of origin ; the part they play 

 in the structure of the land, the relations of the rocks to the scenery 

 and soils, and the economic applications of the strata. This aspect 

 of geology is not one that collectively appeals very strongly to 

 the author, the above matters being treated in a subordinate way 

 when dealt with, and naturally enough. To work at the minute 

 paleeontological and chronological divisions demands not only special 

 knowledge but prolonged and concentrated labour, otherwise the 

 results can be of little value. The rocks, then considei-ed rather as 

 tombs for fossils, are not looked upon with the same affection as- 

 they are by those who are concerned mainly in tracing out the 

 physical structure of a district. 



The " new school," as it is called, is doing work on admirable 

 lines. As Dr. Smith W^oodward has remarked, "The variations of 

 an organism in time and space, and its successive migrations, can 

 only be ascertained by more detailed field-work and more precise 

 labelling than has hitherto been customary among palgeontologists" ;. 

 indeed, " a most exact and exhaustive method of collecting " is 

 necessary.^ The work before us should therefore do much to 

 stimulate further research on these lines in the Jurassic areas. 



In considering this important task it is evident that to meet 

 the requirements of both field -geologist and field-paleeontologist 

 two systems of geological nomenclature are requisite — the one 

 dealing with formations, the other with epochs. In the new 

 Guide to the Fossil Mammals and Birds (British Museum), lately 

 noticed in the Geological Magazine, this is fully recognized, the 

 author (Dr. Smith Woodward) observing, "It is just because rock- 

 formations in difi'erent parts of the world so rarely are equivalent 

 that a time-scale is needed to which each can be referred." 



We should not omit to mention that the present author deals 

 briefly with the scattered superficial deposits of the Cheltenham 

 district, but these have not yet been mapped out in detail, and, as 

 he truly remarks, their history "remains to be written." A fuller 

 knowledge of the valley drifts will no doubt throw light on the 

 popular subject of river-development. Meanwhile the subject has 



* Proc. Geol. Assoc, vol. xviii, p. 429. 



