572 Reviews — Cottesicold Field Club. 



above. The author considers his theory more satisfactory than others, 

 because it "does not require any supposed removal of either nitro- 

 genous matter or the fibmus tissues of plants, neither does it require 

 the assumption of bacterial action deep underground in the presence 

 of salt water ". 



We think that some field evidence is desirable to support this 

 interesting idea. The present writer has seen something of tropical 

 lagoons in the quest of oil, but he has not seen oil films on any of 

 them (except where oil rock crops out beneath). If such a 

 phenomenon does occur it certainly is either invisible or unusual. 

 The author is careful, however, to point out that he does not wish to 

 apply his explanation of the formation of oil to every case. 



T. 0. B. 



IX. — CoTTEswoLD Naturalists' Field Club. 



TTJ'E have befoi-e us part iii of vol. xvii of the Proceedings of this 

 T T Club. It contains records of sundry excursions, including 

 one to Cirencester (with a view of the Eoyal Agricultural College), 

 and another to Brecon (with views of the Brecon Beacons, Llangorse 

 Lake, etc.). The original articles are mainly geological. The 

 indefatigable secretary, Mr. L. liichardson, contributes a "Memoir 

 explanatory of a map of part of Cheltenham and neighbourhood, 

 showing the distribution of the sand, giavel, and clay". The 

 map is a colour-printed geological edition of yheet 26 jS^.E. 

 (Ordnance six-inch map). The amount of detail is not great, but 

 the map clearly shows, by means of six tablets and colours, the 

 distribution at the surface of Lower and Middle Lias clays, and Drift 

 gravel, sand, and bog. The reproduction of the map must have been 

 costlj', but it should be of practical service. Details of the strata and 

 their fossils are given in the memoir, the materials having " been 

 acquired little by little over a period of at least ten years ". There 

 is an analysis of Lower Lias clay, also notes on economic uses of the 

 deposits, their soils, and supplies of water ; and there are illustrations 

 of brick- works, clay and sand-pits. Dr. J. H. Garrett supplies an 

 appendix " On the Local AVaters of the Town of Cheltenham ". The 

 mineral waters are of especial interest, as coming from the Liassic 

 clays, and from the fact of " the cfuality of the yield of no two wells 

 being alike, but often quite distinct and different, though the wells 

 be only a short distance apart". 



Dr. E. A. Newell Arber is author of a paper on " The Fossil 

 Plants of the Forest of Dean Coalfield ", illustrated by three plates. 

 The floras of the productive strata all belong to the Upper Coal- 

 measures ; and they include forty-four species, all known to occur 

 elsewhere in Britain. The author observes that "The Forest of 

 Dean is not an outlier of tlie South Wales coal-field, as has often been 

 supposed. It is more closely related to the Badstock and Bristol 

 coal-fields. There are no equivalents in the Forest of Dean of the 

 Middle Coal-measures (White Ash Series) or Transition Coal-measures 

 (Pennant Grit) of South Wales, and the massive Forest of Dean 

 Stone belongs to a higher horizon than the Pennant Grit, with which 



