Sept. 2 2, 1881] 



NATURE 



497 



SCOTIAND 



South. — Beds of the so-called " Lower Old Red Sandstone " 

 witli fi^h and crustacean^-, included in Prof. Geikie's " Lake 

 Orcadie, Lake Caledonia, and Lake Cheviot," underlying uncon- 

 formably the Old Red Sandstone and Lower Calciferous Sand- 

 stone, and resting unconformably on Older Crystalline rocks. 

 Thickness in Caithness about 16,200 feet. The author con- 

 sidered that all these beds were representative of one another in 

 time, deposited under lacustrine or estuarine conditions, and, as 

 their name indicated, forming a great group intermediate between 

 the Silurian, on the one hand, and the Devonkan on the other. 

 He also submitted that their importance, as indicated by their 

 great development in Ireland and Scotland, entitled them to a 

 distinctive name, such as that proposed. 



On the Discoz'a-y of Coal-Meastcres undtr New Red Sandstone, 

 and on tlie so-called Permian Rocks of St. Helenas, Lancashire, 

 by A. Strahan, M.A., F.G.S., Geological Survey of England 

 and Wales. — The Trias has been penetrated, during the last few 

 years, by three collieiy shafts and three boreholes in the d^^tlict 

 bordering the St. Helen's and Wigan coal-fields on the south. It 

 was thiimer than might have been expected, while the Permian 

 formation was altogether absent. This latter formation was 

 believed to underlie the Trias, but to be overlapped, so as not to 

 appear at the surface, excepting at St. Helen's Junction, where 

 a marl-bed, and a soft jandstone beneath it, 30 and 90 feet thick 

 respectively, and supposed by Messrs. Binney and Hull to be 

 Permian marl and Lower Permian sandstone, w ere found in a 

 quarry and a ^\ ell. The Bold Hall Colliery shaft, at about one 

 mile from the outcrop of supposed Permian rocks, proved the 

 shale to maintain its thickness, but the sandstone to l^e 57 feet 9 

 inches only. The Coal-Measures Mere entered at 186 feet, and 

 penetrated to a depth of iSoo feet from the surface, when the 

 Florida Mine was met with. The red staining due to the Trias 

 extended to a depth of 365 feet in the Coal-Mea^ ures. The 

 Collins Green Colliery shafts, at the same distance from the 

 boundary of the Trias, but three-quarters of a mile north-east of 

 Bold Hall Collitry, proved the shale to be 22 feet, and the sand- 

 stone 44 feet in thickness. The latter contained spherical con- 

 cretions of iron pyrites, binding the grains of sand in their 

 original position in jilains of bedding. The Coal Measures were 

 entered at 310 feet 10 inches, and penetrated to the Florida 

 Mine at 1667 feet 7 inches from surface. They were red for 

 152 feet. The dip of the so-called Permian was to the south- 

 east at 6", that of the Coal-Measures at 10°. The Haydock 

 Colliery shafts (Lyme Pits), at the same distance from the boun- 

 dary of the Tiias, are one mile north-ea-t of Collins Green. 

 The shale and sandstone had diminished here to 9 feet and 7^ 

 feet respectively. Tlie Coal- Measures were penetrated to a depth 

 of 97 feet 2 inches, or 413 feet 3 inches from surface. In the shafts 

 of this and the Collins Grem Colliery, the unconfoni.ity of the 

 red sandstone and the Coal-.Measures was clearly vi-ible. The 

 above sections show that the so-called Permian marl and sand- 

 stone thin out gradually from west to east, the low^er thinning 

 out first, and not the upper, as would have been the case if they 

 had been unconformably overlapped by the overlying beds. 

 They also thin out to the south, as proved by a borehole near 

 FaruHurth, three miles south of St. Helen's Junction, which, 

 after penetrating 124 feet of yellow and white sandstone, passed 

 through 3 feet of red and w hite clay, 3 feet of red sandstone, 

 and entered purple marls with bands of limestone, belonging to 

 the Coal-Measures. The so called Permi.an beds, though un- 

 conformable to the Coal-Measures, are quite conformable^to the 

 Trias, and are ovei lapped in consequence of an attenuation in 

 themselves, and not through having sulTered denudation before the 

 Trias was deposited upon them. Considering also their litho- 

 logical similarity to the Trias, it seems that they should be classed 

 with tliis formation rather than with the Permian. The Permian 

 rocks are probably ab ent we-t of Warrington, for two bore- 

 holes at Parkside and Winwick, commencing in tlie Pebble beds, 

 entered the Coal-Measures at 291 and 341 feet respectively with- 

 out encountering them. The Trias contained a bed of shale 

 about 30 feet thick, and was based by soft sar dstone with twig- 

 shaped concretions of iron pyrites. Like the sjjherical ncdules 

 of Collins Green, these probably ow^ed their origin to the action 

 of Coal-Measure water, with sulphides in solution, acting on the 

 colouring matter (peroxide of iron) of the Trias. The Coal- 

 Mea.-ures consisted of purple and green marls, and at Winwick 

 were associated with limestone. They, and the same beds found 

 in the Farnworth boring, are precisely similar to the well-known 

 Whi-ton limestone, and like it contain the M'croconchiis car- 



bonarius. These limestones are probably the equivalents of the 

 Ardwick limestone series in the Upper Coal-Measures of Man- 

 che.-ter,' and may be found to be underlain by representatives of 

 the coal-seams which are found in connection with it. Without 

 doubt they must be everywhere underlain by the whole of the 

 productive Middle Coal-Mea-ures, but at a great and unknown 

 depth, though there is reason to believe that the thickness of 

 barren measures would be less in West Lancashire. 



Remarks upon the Structure and Classification of the Blastoidea, 

 by P. Herbert Carpenter, M.A.— The author and Mr. R. 

 Etheridje, jun.,' who are prepanng a joint memoir upon the 

 Blastoidea, have arrived at the following conclusions respecting 

 the group : — It is very doubtful whether the genus Pentremites 

 occurs at all in Britain. Some b.adly-pre^erved fragments from 

 the Devonian and the Scotch Carb mifcrou-s are possibly refer- 

 able to it ; but most of the Blastoids (besides Codaster) which 

 occur in the Carboniferous Limestone belong to the genus 

 Granatocrinus, Troost., which is represented by some seven or 

 eight s; ecies. Cu jiberland's iilitra el'-ip:ica is the representative 

 of a new genu", distinguished by the eccentric position of the 

 spiracles. Codaster is a true Blastoid, and not a Cystid, .-is sup- 

 posed by Billings. The slit-hke opeuings of its hydrospires are 

 nearly on the same level as the ambulacra, which do not conceal 

 theui at all. In the ordinary Blastuids, however, they are beloW 

 and concealed by the ambulacra, opening externally by pores at 

 the sides of the latter. There are various intermedia'.e forms 

 between these two extremes, in which the hydrospiral slits are 

 more or less oncealed by the ambulacra, but are partially visible 

 at their sides. It is proposed to group the species thus distin- 

 guished into a genus Ptntrcmitidea, which is represented in 

 Britain by the little Pentremites acutiis, Sowerby, in Belgium by 

 P. carycphylla'us, and in Spain by P. Pailleti, De N'ernoui', for 

 which last the name PentremitUea had been already propo ed by 

 D'Orbigny. An arrangement of this kind has been already 

 su/gested by Billings. Ihe di;covcries of Rofe, Wachsmuth, 

 and Hamliach, respecting the perforation of ihe lancet-piece by 

 a longitudinal canal, are confirmed. This canal probably lodged 

 the water-vessel, which must have been devoid of any tentacular 

 extensions, as in some Holothurians, and in the arms of cert.ain 

 Comalulcc. Respiration w.as effected, however, by means of the 

 hydrospires. The pores usually found at the sides of the ambu- 

 lacra were not the sockets for the attachment of the appendage^, 

 but led downwards into the hydrospires, serving to mtroduce 

 water, which made its way out through the sjiracles. The 

 genital ducts probably opened into some portion of the hydro- 

 sipires, as they do into the closely similar structures of the 

 Ophiiiroidea, and the ova were discharged through the spiracles. 

 Billings' statements are confirmed respecting the existence in 

 many sp.cies cf a single or possibly double row of jointed 

 appendages along each side of the ambulacra ; but these 

 appendages are not hoxologous with the pinnules of the 

 Crinoidea. In perfect specimens the peristome is covered in by 

 a vault of small polygonal plates, any definite arrangement of 

 which is rarely traceable. E.xten ions of this vault were con- 

 tinued down the sides of the ambubicral grooves, which could 

 thus be closed in completely and converted into tunaels, as in 

 recent Crinoids. The classification of the Blastoidea must 

 depend entirely upon morpholo.;ical principles. Mere differences 

 in the rel.ative sizes of the calyx plates are of very little systematic 

 value ; and differences in the numbers of side plates on given 

 lengths of the ambulacra are absolutely worthless. On the 

 other hand, the structure and relative positions of the hydro- 

 spires and spiracles are morphological characters of much 

 systema'-ic value. 



On the Extension into Essex, Middlesex, and other Inland 

 Countie', of the Mundeslc)' and Westleton Beds, in Relation to 

 the Age of certain Hill-gravels, and of some of the Valleys of the 

 South of Englanl, by J. Prestwich, MA., F.R.S., Professor of 

 Geology in the University of Oxford. — The author gives in this 

 paper the result of observations commenced more than thirty 

 years since, but delayed publication in consequence of doubts 

 caused by the complexity of the phenomena. As mentioned in 

 the preceding paper, a peculiar group of land, freshwater, and 

 marine beds occupy, on the Norfolk coast, a zone between the 

 Chillesford Clay and the Lower Boulder Clay. As we proceed 

 southward, the land ar.d freshwater conditions are gradually 

 eliminated, and marine conditions then alone prevail. PoDrly 



' This identification was pointed out by Mr. De Ranee in the Trans- 

 Manche&ter Geol. Soc. for 1880. (" Further Notes of Triassic Borings near 



Warrington") 



