40 



THE GEOLOGIST. 



course of a river during the time of deposition of some of the later Tertiary 

 beds ; and a flood probably swept into the layers of broken fragments of 

 chalk and clay, together with, the numerous land-shells with, which, they 

 are studded." About 300 or 400 yards from the spot is a light buff- 

 coloured sand, and on the south, side of the pit are hardened blocks of 

 sandstone. The writer thinks this sand was once a part of the Plastic 

 Clay series, at one time covering the district, and of which there are said 

 to be still some remains in the south-east part of the forest. This appears 

 to be, according to the subsequent description, a section showing the " grey 

 weathers " in situ. These " boulders " are stated to occur in great numbers 

 in the valleys, especially at Lockeridge and Clatford Bottom, " where they 

 are heaped upon one another in the most promiscuous manner, as if they 

 had been dropped by icebergs." Many are of large size, 90 to 100 tons. 

 An outline of the Bagshot sands and clays also occurs in the Savernake 

 Forest. Of the flora we can only say that it is conspicuously and con- 

 cisely recorded in separate paragraphs, with bold headings, and is sub- 

 stantially upon the plan adopted by Professor Babington for his ' Flora of 

 Cambridge.' The book is illustrated with a small photographed map of 

 the district, reduced from the ordinary 1-inch survey to within the space 

 of a double page. It wants a scale to indicate distances, and this might 

 be usefully added. 



Philosophical Transactions of the Royal Society. Part I. Yol. CLIIT. 



1863. 



This part is a highly important one, containing papers " On the Relation 

 of Radiant Heat to Vapour," by Professor Tyndall ; " On the Strains of the 

 Interior of Beams," by the Astronomer Royal, Mr. Airy ; " On the Re- 

 flection of Polarized Light from Polished Surfaces, Transparent and Me- 

 tallic," by the Rev. Professor Haughton ; "On the Exact Forms of Waves 

 near the Surface of Deep Water," by Dr. Rankine ; " The Photo-Chemical 

 Researches of Professors Bunsen and Roscoe ; " " On the Immunity of the 

 Stomach from Injury from its ownSecretions,"byDr.Pavy; "On Thallium," 

 by Mr. Crookes ; and other very valuable papers ; but the chief interest to 

 our readers will be the appearance in it, in full, of Professor Owen's memor- 

 able paper, read in November, 1862, and briefly reported in our columns. 

 The present memoir is perhaps the most complete that ever was given at 

 first hand of any specimen approaching in novelty and singularity to the 

 present Solenhofen fossil, a drawing of which is given of natural size, 

 executed with great care and skill by Mr. Dinkel. Other illustrative 

 plates accompany the paper, which must be read by those who are inter- 

 ested in the subject, as no abstract would convey more information than 

 the notices and articles we have already printed ; and the greatest value 

 of Professor Owen's description lies in the minuteness and details of the 

 numerous comparisons he has made with the bones of recent birds and 

 fossils, Pterodactyles, and the logical conclusions he has deduced from them. 

 The Professor admits the cast of the brain, to which we drew attention in 

 our opening number of last year ; but he assigns to a fish a portion of organic 

 substance in the slab upon which Mr. Mackie has made some comments 

 in the ' Popular Science Review,' for the purpose of showing that it is as 

 like a bird's beak with teeth as a fish's jaw. The portion is, however, too 

 obscure for any positive determination, and it will be better not to believe 

 it either a fish's jaw or the Archreopteryx beak at present, but to con- 

 tinue to search diligently for further specimens. 



