NA TURE 



\Sipt. 2 2, i88i 



marked as the marine evidence is in Suffolk, this evidence i^ 

 entirely \\anting furtlier inland, and %\e have only levels, juper- 

 posiiion, and structure to rely on in correlating the fragmentary 

 outliers into which these beds finally resolve themselves. Again 

 on the coast of the Eastern Counties, this group forms a nearly 

 level plain but little above the sea-level, resting everywhere on 

 an undistm'bed or very slightly eroded bed of Chillesford Clay, 

 and being succeeded, with but slight evidence of denudation, 

 by the Lower Boulder Clay, or by the Glacial sands and gravel ; 

 whereas, as it trends inland, it attains a considerable elevation 

 above the sea level, passes unconformably over the older Tertiary 

 strata, and has been subjected to a great amount of denudation. 

 On the other hand, the old land, which seems to have extended 

 from the eastward as far as the Norfolk coast, is now in great 

 part below the level of the German Ocean. Further, whereas 

 the succeeding Glacial beds all show a drift from northward to 

 southward, this is the only case that has come under the author's 

 notice of a marine drift from southward to the northward. The 

 Westleton Bed^, in their more typical aspect, consist of quartzose 

 sands full of flint pelililes, almost as much worn and as nume- 

 rous as in the Lower Tertiary sands of Addington. The author 

 then proceeds to trace the beds through Essex, and gives a series 

 of railway sections showing these beds, exhiljiting usually tlie 

 appearance of a white gravel, with intercalated ocbreous beds, 

 and reposing on a very eroded surface of the London Clay. In 

 traversing the beds farther westward they undergo further modi- 

 fication. Certain characters remain, however, persistent, and 

 on these we have to rely : (i) The shingle is composed essen- 

 tially of chalk flint peliljles, becoming less worn as we approach 

 the .southern limits of the deposit ; (2) it often becomes much 

 mixed with flint pebbles and sub-angular fragments of compact 

 sandstone derived from the underlying Tertiary strata ; (3) the 

 chert and ragstone fragments often so increase in numbers as to 

 constitute a large portion of the gravel. They are worn and 

 sub-angular, and the chert is identical with the chert of the 

 Lower Greensand of Kent and Surrey ; (4) the pebbles of white 

 and rose-coloured quartz, of Lydian stone, and of white quartzite 

 become rarer, and in places are wanting. The Lydian stone 

 and some of the small quartz pebbles may be derived, w ith the 

 chert, from the Lower Greensand, but this will not account for 

 the great number of quartz pebbles found in the Eastern Counties. 

 The quartzite pebbles are equally large, but lighter coloured and 

 more ovoid than those of the New Red. They probably hax'e 

 drifted from a continental area on the east, the author having 

 found similar beds in parts of Belgium ; (5) the absence of 

 northern drift. The author reserves for another occasion the 

 description of the beds next in order ; but he •\\ould mention 

 here that the Boulder Clay and some Glacial gravels occupy in 

 Herts and Birrks a lower horizon than the Westleton Beds. It 

 would therefore appear that, while the eastern area was .sub- 

 merged, and the strata follo\^ed in regular succession upon a 

 surface which did not undergo denudation, the southern and 

 western area was slowly elevated, and underwent partial denuda- 

 tion before the Upper Boulder Clay was deposited. Previous 

 to the period of the Westleton and Munde-ley beds, it is pro- 

 bable th.at ihe denudation of the Weald had hardly commenced. 

 The area ^\as spread over by Cretaceous strata under water at 

 the beginning of the Crag period (the Lenhani beds), and 

 judging from the character of the beds which fringe the Nrrth 

 Wealden area at Chelsfield, Cherry Down, &c., the author 

 concludes that there was land south of this fringing shingle, 

 whence the great mass of Chalk-flints and of Lower-Greensand 

 cherts and ragstone must have been derived. This mass of 

 debris serves to attest to the great extent of the^e strata that have 

 been removed from the Wealden area while yet it Aias an 

 elevated and not a depressed area. After the rise of the area 

 over which the Westleton Beds extended, it underwent exten- 

 sive denudation, and it was at this period that the great plain of 

 the Thames Valley received its first outlines, although it was 

 not until much later that the river valley received its last impress. 

 A ContrUnilicn to Seismohgy, by Prof. J. Milne and T. Gray, 

 B.Sc. — It was pointed out that earthquake motion is generally of 

 a very irregular character, that it usually begins gradu.ally, reaches 

 a maximum somewhat suddenly, and afterwards passes through 

 several minima and maxima. The period of vibration of a 

 great number of earthquakes observed by the authors varied 

 betiveen half and one-fifth of a second, while the t jtal time of 

 disturbance varied from one to three minutes. Reasons were 

 given for believing that earthquakes which la^t for a long time 

 are propagated further than those which last for a short time, 



even when the intensity of the latter is the greater. As to the 

 determination of the origin of shock, the great value of accurate 

 time observations was pointed out, and a sketch of different 

 modes of making such observations was given. Explanations 

 were entered into with regard to the rotation of bodies during 

 earthquake shocks. 



The Glacial Geology of Ci-iifral Waks, by Walter Keeping, 

 M.A. — The author adduces evidences to show that Central Wales 

 was covered with snow and ice during the glacial period, but 

 all the glaciers of which we have any traces were of strictly 

 local character, each confiucd to its own drainage area in the 

 present valley system. There is no evidence of any great ?!ter de 

 glace, nor of any marine submergence in recent geological times. 

 On the Lo7ver Kcuper Sandstone of Chesliire, by A. Strahan, 

 M.A., F.G.S., Ge ilogical Survey of England and Wales. — This 

 paper deals with some of the results of the re-.-urvey of parts of 

 Cheshire, which have been already described in detail in the 

 Geological Survey Memoirs "On the Neighbourhood of Pres- 

 cot" (third edition), and "On the Neighbourhood of Chester." 

 Several sections, of which the best are at Runcorn and Frod- 

 sham, show that there is a strong and constant divi-ion between 

 the waterstones and the Keuper Easement Beds. These w ere 

 formerly cla.^sed together under the name of Lower Ktuper 

 Sandstone, but, so far as the re-survey has been carried, are 

 now distinguished on the maps. The old and new classifica- 

 tions may be compared as follows : — 



Old Classification. New Classification. 



Keuper Marl Keuper Marl. 



( Waterstones. 

 Lower Keuper Sandstone ... -j Lower Keuper Sandstone or 



( Basement Beds. 



SECTION D— Biology 

 Department of Anatomy and Physiology 



On the Conario-hypofhysial Tract, or the Pireal and 

 Pituitary Glands, by Prof. Owen, C.B., F.R.S.— The author, 

 referring to the latest contributions to the subject of his paper, 

 remarked that they bore upon the functions of the so-termed 

 "glands." Prof. Sapolini, in his work " L'Aire de la Selle 

 Turcique " (8vo, iSSo), concludes that " the pituitary gland 

 secretes the fluid of the ventricles of the brain." Prof. Ed. 

 Van Beneden, in reference to the supposed pituitary gland in 

 Ascidians, regards it as their renal secretory organ (Archiz'es de 

 Biologie, 8vo, 18S1). In pursuance of his aim, which w.as 

 homological. Prof. 0« en traced the modifications of the pineal 

 and pituitary bodies and connecting parts from man down to the 

 low est fishes possessing a brain ; and noted the progressively 

 increased relative size and retention of tubular structure of the 

 tract, including the so-called "pituitary gland," "infundi- 

 bnlum," "third ventricle," and " pineal gland," as the vertebr.ate 

 series descended ; also the further extension of the pineal part of 

 the tract, beyond the brain, t 1 its perforation of the cranium, 

 leaving the so-called "foramen parietale" in some existing and 

 in many extinct Reptilia. These phenomena were then tested 

 and compared with concomitant phases in the development of 

 the vertebrate, especially the mammalian, embryo. It was 

 shown, as had been noted by previous embryologists, that prior 

 to the permanent anterior outlet of the digestive sac, a produc- 

 tion from such sac extended to the large cerebral vesicle, >ub- 

 sequently reduced to a "third ventricle"; whence the hollow 

 tract was continued onward to the epithelial covering of the head, 

 by which it was closed. The lower pharyngeal beginning of 

 this trans-cerebral tract also became closed and modified as the 

 " pituitary body." The upper continuation became modified, 

 .and in higher vertebrates clo' ed as the " pineal body" ; but the 

 intermediate portion of the tract retained its primitive hollow 

 condition as the "third ventricle" and " infundibulum." The 

 "sella turcica "in mammals, lil;e the "foramen parietale" in 

 cold-blooded vertebrates, were modifications in the skeleton of 

 parts f>f the " conario-hypophysial tract." This tract, under all 

 its modifications, marked vertically the division between the 

 "cerebrum" and the "optic lobes," or divided the "fore- 

 brain " from the "hind-brain." 



The author next proceeded to point cut the homologies of the 

 parts of the neural axis in invertebrates with those of vertebrates. 



The so called "supra-cesoph.igeal ganglion or ganglions " in 

 the former were homologous with the "cerebrum, or cerebral 

 hemispheres " in the latter. The so-called " sub-cesnphage.al 

 masses " in invertebrates answered to the mes-and ep-encephalic 



