.not plentiful in it, and the peat contains an abundance 

 of fresh-water and marsh plants, but I found no fresh- 

 water shells. The only animal remains I obtained 

 are the upper part of the skully and horn-cores of 

 Bos longifrons, but I was told that bones had fre- 

 quently been washed out of it. Among the plants a 

 species of Cyperus was abundant, and Sphagnum was 

 also plentiful. Indeed the nature of the peat-bed 

 indicates its formation under just such marshy con- 

 ditions as geologists have assumed the bed of the 

 German Ocean to have been in before the submer- 

 gence took place which brought the sea-water over 

 it, and so converted England into an island. 



The discovery of this remnant of a once extensive 

 peat-bed, uncovered only in part even at extreme low 

 water spring-tides, is therefore interesting as con- 

 firming the geological speculations concerning the 

 old marshy plain over which the German Ocean now 

 extends. 



A LIST OF LAND AND FRESHWATER 

 SHELLS OCCURRING NEAR LONDON. 



AS there have been so many queries in Science- 

 Gossip lately, about localities for land and 

 freshwater shells, I thought it might interest your 

 readers to know that I have observed the following 

 near London. 



Aquatic. — Spkarium cor mum, Chislehurst, &c. ; 

 5". lacustre, Chislehurst and Enfield ; Pisidium 

 amnicum, Enfield (Middlesex) ; P. fontinale, St. 

 Mary Cray ; P. pusillum, in a ditch at Bickley ; P. 

 nitidum, in a pond on Chislehurst Common ; Unio 

 tumidus, Enfield, very abundant ; U. pictorum, 

 Enfield ; Anodonta cygnea, Beckenham, Kent (the 

 form I have found is exceedingly large and swollen, 

 and is probably the var. incrassata) ; A. anatina, 

 plentiful at Enfield ; Neritina fluviatilis, Enfield ; 

 Paludina vivipara, Enfield ; Bithynia tentaculata, 

 St. Mary Cray ; Valvata piscinalis, St. Mary Cray ; 

 Valvata cristate, occasionally at St. Mary Cray ; 

 Planorbisnitidus, Chislehurst Common ; P. naiitilens, 

 Chislehurst Common ; P. albus, St. Mary Cray and 

 Enfield ; P. spirorbis, Chislehurst Common ; P. 

 ■vortex, St. Mary Cray ; P. carinatus, Enfield, scarce ; 

 P. complanatus, St. Mary Cray ; P. comeus, Enfield ; 

 P. contortus, Chislehurst and Enfield ; Physa hypno- 

 rum, ditch at Bickley ; P.fontinalis, St. Mary Cray; 

 Limnica peregra, St. Mary Cray, &c. ; L.peregra, var. 

 vvata, Bromley ; L. peregra, var. labiosa, Bromley ; 

 /.. auruularia, Enfield ; L. stagnalis, Enfieid and 

 Chislehurst ; L. stagna/is, var. fragilis, Enfield ; L. 

 palnstris, St. Mary Cray and Enfield ; L. truncatula, 

 in ditch at Bickley ; Ancylus lacustris, Chislehurst. 



Terrestrial.— Arion atcr, Chislehurst, &c. ; 

 Limax agrcstis, Chislehurst, &c. ; L. maximus, 

 Chislehurst, &c. ; Succinca putris, St. Mary Cray ; 

 S. ehgans, St. Mary Cray ; Vitrina pellucida, Chisle- 

 hurst, &c. ; Zonites ccllarius, Chislehurst, &c. ; Z. 



nitiduhis, Chislehurst, &c. ; Z. crystallinus, Chisle- 

 hurst, &c. ; Z.fulvus, Chislehurst, scarce; Z. nit id its, 

 Enfield ; Helix pomatia, Caterham, Surrey ; IP. 

 aspersa, Chislehurst, &c. ; H. nemoralis, Chislehurst, 

 &c. ; H. nemoralis, var. horlensis, Chislehurst, &c. ; 

 H. Cantiana, Chislehurst, &c. ; H. rufescens, Chisle- 

 hurst, &c. ; IP. hispida, Chislehurst, &c. ; H. virgata, 

 Caterham and St. Mary Cray ; //. capcrata, Chisle- 

 hurst and Caterham ; capcrata, var. ornata, Chisle- 

 hurst and Caterham ; H. ericetornm, Caterham and 

 St. Mary Cray; H. roticndata, Chislehurst, &c. ; 

 H. rotundata, var. alba, Chislehurst, two specimens ; 

 H. pulchclla, var. costata, Chislehurst and St. Mary 

 Cray ; H. lapicida, Caterham ; Bulimus obscurus, 

 Chislehurst, &c. ; B. obscurus, var. alba, Chislehurst ; 

 Pupa umbilicata, Chislehurst and St. Mary Cray ; 

 Clausilia rugosa, Chislehurst and St. Mary Cray ; C. 

 lamiuata, Caterham ; Cochlicopa lubrica, Chisle- 

 hurst, &c. ; Carychium minimum, St. Mary Cray ; 

 Cyclostoma elegaus, Caterham and St. Mary Cray. 



It may be worth while to say that I have col- 

 lected all the above during last year (1882), and that 

 all those mentioned as occurring at Enfield were 

 obtained in the course of two days. 



Glen Druid, Chislehurst. S. C. C. 



ON THE DISCRIMINATION OF DIFFERENT 

 SPECIES OF WOOD BY A MICROSCOPI- 

 CAL EXAMINATION OF SECTIONS OF 

 BRANCHES. 



IN the course of seeking for microscopical fungi in 

 the woods, I often picked up sticks which I 

 was at a loss to assign to their true origin. This in- 

 duced me to make sections of the branches of com- 

 monly occurring trees, with a view to make myself 

 familiar with the structure of the wood. 



I was somewhat surprised at the differences exhi- 

 bited in the sections, and, pursuing the subject, I 

 have endeavoured to classify the differences of struc- 

 ture, in the hope that this may prove useful to others 

 similarly situated to myself. 



It is not put forth that the classification here 

 alluded to, with the verbal descriptions attached, 

 will answer the purpose completely, but I think 

 that it will assist a person greatly in the determi- 

 nation of a species of wood. Take, for instance, 

 beech and birch, lime and poplar. The differences 

 are striking when the internal structure is examined, 

 not so when merely the external aspect is observed. 



For the perfect determination of a species of wood, 

 authentic sections or accurate drawings of such 

 sections are needed for comparison. 



The character of the pith mass of the medullary 

 rays, of the ducts in the woody tissue, and of the 

 bark, are important elements in the determination of 

 the plant, and will serve as a good guide to the 

 enquirer, and facilitate reference to authentic sections. 



C. J. Muller. 



