July i8, 1872J 



NATURE 



!35 



the catalogues of Mr. Main and Mr. Slonc. ' The probability 

 of the stars being collected into such systems was early suggest>;d 

 by Mitchell and the elder Herschel.t I 'ne of the most remai'k- 

 able instances pointed out by Mr. Proctor are the stars /3, 7, 5, e 

 of the Great Bear, which have a community of proper motions.? 

 whUe o and tj of the same constellation have a proper motion in 

 the opposite direction. Now, the spectroscopic obsei-vations 

 show that- the siais j8, 7, 6, f, s,'havc also a common motion of 

 recession while the s'ar o is approaching the earth. The star 

 7) indeed appears to be moving from us, but it is too far from a 

 to be regarded as a companion to that star. 



Table I. — Stars moving from Sun 



Table II. — Stars approaching the Sun 



Although it was not to be expected that a concurrence would 

 always be found bcUVLCn the proper motions which indicate the 

 apparent melions at right angles to the line of sight and the 

 radial motions as ditcovered by the speciroscope, still it is in- 

 teresting to remark that in the case of the stars Castor and Pollux, 

 one of which is approaching and the other receding, their proper 

 motions also are different in direction and in amount ; and fur- 

 tl er, that 7 Ltonis, vhich has an opposite radial motion to a 

 and /3 of the same constellation, differs frt-m these stars in the 

 direction of its proper motion. 



* See •'Preliminary Paper on certain Drifting Motions of Stars," Proc. 

 Koy. Soc vol. xviii, p. 169. 



t Sir William Heischcl writes :-" Mr. Mitchell's admirable idea of the 

 .^tars beirg collected into systems appears to be extremely well founded, and 

 is every day more confirmed by observations, though this does not take away 

 the probability of many stars being still as it were solitary, or, if 1 may use 

 the expression, intersystematitial. . . A star, or sun such as ours, may 

 have a proper motion within its own system of stars ; vhile at the same time 

 the whole starry system to v hich it belongs may have another propermotion 

 totally different in quantity and direction.'* Herschel further says, "and 

 sh^juid there tie found in any particular part of the heavens a cone urrense of 

 proper motions of quite a different direction, we shall then begin to form some 

 conjectures which stars may possibly belong to ours, and which to other 

 systems. '—Phil. Trans. 1783, pp. 276, 277. 



t Mr. Proctor, speaking of these stats, says;— "Their drift i.s, I think, 

 most significant. If, in trulh, the parallelism and equality of ULOtion are to 

 be regarded as accidetital, the coincidence is one of most remarkable charac- 

 ter. But such an interprelaiion can hardly be looked upon as admissible 

 when we remember that the peculiarity is only one of a series of instances, 

 some of which are scarcely less striking." — '' Other Worlds than Ours," 

 p. 269, and paper in Proc. Roy. Soc. vol. xviii. p. 170. 



It scarcely needs remark that the difference in breadth of the 

 luie H /3 indifferent stars affords us information of the difference 

 o'' density of the gas by which the lints of absorption are pro- 

 duced. A discussion of the observations in reference to this 

 point, and to other considerations on the physical condition of 

 the stars and nebula:, I prefer to reserve for the present. 



EXCURSION OF THE GEOLOGISTS' ASSOCIA- 

 TION TO GUILDFORD AND CHILWORTH, 

 JUNE 1 

 'T'HE party first proceeded to examine the section of the 

 •*■ " Woolwich and Reading Beds," just north of the station. 

 Thi; section was described by Mr. Prestwich in 1850 (see 

 Quarterly Journal Geological Society, vol. vi. p. 260, fig. 6) 

 not long after it had been exposed by the railway-cutting. A 

 year ago it was laid bare afresh when widening the railroad ; 

 but already the slipping of the clays has obliterated some points 

 of interest. Traces of the shell beds, with Cyruita and Os/n-a, 

 below the representatives of the " Oldhaven beds," are to be 

 found at the base of a telegraph post, 104 yards south of the 

 road bridge ; and the underlying mottled clays, with a dip of \' 

 to the north, arc easily recognised for about 190 yards to the 

 south, where a small valley (about 50 yards across) has been 

 formed by denudation out of the sand and lowest green sandy 

 clays resting on the Chalk, which forms the northern foot of the 

 Hogsback .or Surrey lange. Here the Chalk is seen to ba 

 traversed In every direction with fis-ures, often "shckensided," 

 horizontally or nesrly so, some empty, some filled with vein 

 flint, and some with loamy stuff. Nodules and occasional thin 

 lamina; of flint follow the dip of about 6" to the north, and 

 many are in a crushed condition. Bands of marly chalk also 

 lie on the same plane. Some Echir.oderms were met with. 

 The party then proceeded to visit the much larger excava- 

 tion in the Chalk at the entrance of the railway tiuinel. Here 

 the dip, well marked by flints and marly bands, is about 12° 

 to the north. Fossils (Sponges, Kchinoderms, Inoceramus, &c. ) 

 abound in this pit. The usual chalcedonic and quartzy inteiiurs 

 of hollow flints attracted notice, and Prof. R. Jones drew at- 

 tention to facts that seemed to him to bear evidence of flint being 

 a pseudomorph after chalk. They next visited a quarry in 

 the Lower Greensand, on the escarpment overlooking the 

 pathway to Losely. In this section of those Neocomian beds 

 known as the Bargate Stone, the waterworn sand of quarlz, 

 ironstone, lydite, and hard green silicates, is so largely mixed 

 with calcareous fragments (the d,;l't is of shell beds, polyzoan reefs, 

 &c.) that it is here and there cemented together hard and com- 

 pact enough to serve as a building stone and road-metal. Mr. 

 Meyer here directed attention to the horizon at which he obtained 

 an unrolled tooth of I^iiaiioi/oii, indicating the existence of this 

 great Dinosaur at, perhaps, the latest period to which any of its 

 remains as yet known belong. The "false-bedding" of the 

 sands — due to the southward set of prevalent tides and currents, 

 and the probable origin of their materials from the "old pala-o- 

 zoic ridge or shoal," were also studied, and the formation of the 

 escarpment, with the correlative parallel cracks and fissures of 

 the strata. The party then crossed the FeiTy, where St. 

 Catherine's Spring issues, beneath the hill, from a little cive 

 in the red-orange- tinted sand. Here for thirty feet at least the 

 Guildford gap has been found by boring to be occupied liy 

 bouldered chalk and other detritus due to the destruc- 

 tive, and yet conservative, agencies of nature. The soft irony 

 beds of the Lower Greensand were next met with, and followed 

 followed for about a mile, until a short field-lane, crossing the 

 Gault and Upper Gieensand, led into the Chalk-marl (juarry 

 below Warren Farm. Here the loss of the clay beds (Gault) fr. m 

 below, by thtir having been squeezed out along the southern side, 

 had allowed the hard marl-rock to subside inwards and suddenly 

 at the escarpment, and to rest at high angle (70° and more), 

 whilst the Chalk of the hill range above dips only 5° or 6^ As 

 the hard rock bands, here quarried for lime, are followed end- on 

 along the strike (open to-day), the backs of lowei beds form one 

 side of this deep narrow pit ; and the truncated edges of these 

 somewhat bent and much fissured strata warn the instructed eye 

 of the danger of standing either below them or alove them, lest 

 either rain or drought should detach their clinging surfaces from 

 the sloping bed-plane. Large Ammonites and Nautili are the 

 chief fossils met with here ; but I'cctcn Baweri and Tercbratula 

 are also found. In an old excavation in the lane .S>y*//c«/fl has 

 be«n found in the representative of the Upper Greensand 



