502 



♦ KNOWLEDGE ♦ 



[JusE 12, 1885. 



THE BOULDER-CLAY OF CHESHIEE. 



AT the meeting of the Geological Society on May 27, a paper 

 was read " On some Erratics in the Bonlder-clay of Cheshire, 

 &c., and the Conditions of Climate they Denote," by Charles 

 Ricketts, JI.D., F.G.S. 



The author stated that the glacial phenomena of the valley of 

 the Mersey indicate that the country has been entirely covered with 

 ice and snow, resulting solely from the snowfall on its water-slopes 

 and those of the tributary valleys. The glacial stria; coincide in 

 direction with that of the respective valleys, or are in direct con- 

 nection with the contour of the ground. The bottoms of the valleys 

 are usually filled to some extent with irregularly stratified sands 

 and gravels, containing erratic pebbles from which all striae have 

 been removed, probably by currents, of water holding sand in sus- 

 pension. Above these there is a boulder clay containincr a larger 

 proportion of sand and gravel than the boulder-clay proper. The 

 flanks of the valley are covered with nnstratified sand or fracnnents 

 of sandstone derived from the Trias, probably left by glaciers as 

 submarine moraines. The whole is overlain by the true boulder- 

 clay, an unstratified reddish-brown clay containing erratics derived 

 from different and distant localities. This clay originated in the 

 grinding action of the glaciers upon the neighbouring rocks, and 

 was carried out in the form of mud by sabglacial streams of water. 

 The contained pebbles, many of which are smoothed, flattened, 

 scratched, and striated, were carried by and dropped from iceberss 

 and floating ice ; they are so abundant as to indicate that the bay 

 of Liverpool was densely packed with ice. 



The author noticed the occurrence in these beds of masses of 

 contemporaneous sands, gravels, &c., caused ' by changes in the 

 extension of the glaciers, and described a large series of erratics 

 derived from granitic, volcanic, silurian, carboniferous, and other 

 rocks covered with stria; and other glacial markings, and also 

 affording evidence of subsequent exposure to weathering before they 

 were floated away and dropped into the clay. In connection with this 

 weathering of the boulders, the author remarked that in the case of 

 the granitic and volcanic rocks the process differed greatly in degree 

 extending in some granites to the separation of each individual 

 grain throughout the whole mass, and he called attention to the 

 occurrence in Ireland of fragments of disintegrated granite and 

 trap imbedded in moraines, eskers, and Boulder-clay, and to that of 

 Westdale-Crag granite similarly decomposed in the moraines in the 

 neighbourhood of Shap, where also rocks of volcanic origin have 

 become weathered in the same way as some in the Boulder-clay of 

 Cheshire. Fragments of limestone also show traces of erosion, 

 while others have been split into two or more pieces since their 

 glaciation, phenomena also observed in moraine-accumulations in 

 limestone districts. Similar phenomena occur in the case of 

 slaty and other stratified rocks. Some limestone pebbles have 

 been perforated by Mollusca and other marine animals. 



The inference drawn by the author from the facts recorded in 

 his paper is that these weathered boulders once formed portions of 

 moraines on land from which, for a time, the glaciers had receded 

 and that, after a succession of seasons soificient to disintegrate 

 these blocks more or less, an increased snowfall caused such an 

 extension of the glaciers that the blocks were carried down to the 

 sea and conveyed away in icebergs and by floating ice to the spots 

 where they are now imbedded. As they occur at different horizons 

 there must have been a repetition of the advance and retreat of the 

 glaciers such as now occurs in Greenland. 



of art ; but in each and every such effort, while as a 

 ■whole it may be noble, there are errors of detail needing 

 his subsequent correction, and showing the irritability of 

 the conceiving power, whose rapid, spasmodic action could 

 not be controlled to the consideration of momentarily 

 occurring trifles, but passed them by to encounter mightier 

 obstacles. 



An analogy might be drawn between the phenomena of 

 complex uervous exhaustion affecting a very high intellect 

 and the symptoms seen in the athlete suffering from the 

 simple form of the complaint. As the mind of the one 

 aims at gigantic efforts, and can hardly control itself to the 

 consideration of minute details, so the muscles of the other 

 can perform heavy labour, but cannot be maintained under 

 steady command when required to execute some slight 

 muscular effort necessitating absolute steadiness. In both 

 cases there is irritable and spasmodic action. 

 {To he continued.) 



FIRST STAR LESSONS. 



By Richard A. Proctor. • . ' , ' 



THE constellations included in the twenty-four maps of 

 this series are numbered throughout as follows (the 

 names being omitted on the maps, to clear these as far as 

 possible from all that might render the star-grouping less 

 distinct) : — 



6. 



7. 



8. 



9. 



10. 



11. 



12. 

 13. 

 14. 

 15. 



16. 

 17. 



18. 

 19. 

 20. 



21. 



Ursa Minor, the Little Bear 



{a, the Pole Star). 

 Draco, the Dragon (a, 



Thuhan) 

 Cephe^ts, King Cepheus. 

 Cassiopeia, the Lady in the 



Chair. 

 Perseus, the Chariipion {ft, 



Algol, famous variable). 

 Auriga, the Charioteer (a, 



Capella) 

 Ursa Major, the Greater 



Bear (a, /3, the Pointers). 

 Canes Venatici, the Hunting 



Bogs (a. Cor Caroli). 

 Coma Berenices, Queen 



Berenice's Hair. 

 Bootes, the Herdsman (a, 



Arc turns). 

 Corona Borealis, the Nor- 

 thern Crou-n. 

 Serpens, the Serpent. 

 Hercules, the Kneeler. 

 Lyra, the Lyre (a, Vega). 

 Cygnus, the Sican (o, 



Arided ; fi, Alhires). 

 Pegasus, the ITinged Horse. 

 Andromeda, the Chained 



Lady. 

 Triangula, the Triangles. 

 Aries, the Bam. 

 Taurus, the Bull (a, Alde- 



buran ; ij, Alcyone, chief 



Pleiad). 

 Gemini, the Ticins (a, 



Castor ; /3, Pollux). 



22. 



23. 

 24. 

 25. 

 26. 



27. 

 28. 

 29. 

 30. 

 31. 



32. 

 33. 



34. 



35. 



36. 

 37. 

 38. 



39. 

 40. 

 41. 



42. 

 43. 



44. 



45. 



Cancer, the Crab (the 

 cluster is the Beehive). 



Leo, the Lion (a, Regulus). 



Virgo, the Virgin (o, Spica) 



Libra, the Scales. 



Ophiuchua, the Serpent 

 Holder. 



Aquila, the Eagle (a, Altair). 



Belphinus, the Dolphin. 



Aquarius, the Water Carrier . 



Pisces, the Fishes. 



Cetus, the Sea Monster (o, 

 Mira, remarkable va- 

 riable) . 

 ' Eridanus, the River. 



Orion, the Giant Huntej 

 {a, Betelgeux ; ^, Rigel). 



Canis Minor, the Lesser Dog 

 (a, Procyon). 



Hydra, the Sea Serpent (a, 

 Alphard). 



Crater, the Civp {a, Alices). 



Con-US, the Crow. 



Scorpio, the Scorpion (a, 

 Antares). 



Sagittarius, the Archer. 



Capricornus, the Sea Goat. 



Piscis Australis, the Sou- 

 thern Fish (o, Fomal- 

 haut). 



Lepus, the Hare. 



Columla, the Dove. 



Canis Major, the Greatey 

 Dog (a, Sirius). 



Argo, the Ship. 



SHOOTING STARS. 



THE passage in our last from the Annuaire for 1836 led 

 to the following amusing communication from an 

 American correspondent of the Penmj Magazine : — 



Having read in various publications, accounts of the 

 appearance of what are there termed shooting stars, which 

 happened in Xorth America on the morning of Nov. 13, 

 1S33, and as such accounts are in many respects erroneous 

 as to facts and, in my humble opinion, as to the causes ; I, 

 having been myself an eye-witness of the phenomenon in 

 question, think it but right, in aid of science, to give a 

 statement of such circumstances as came within my obser- 

 vation, the truth and correctness of which may be relied 

 upon, leaving it to more enlightened minds to find out the 

 operating cause of such occurrences. 



Having awoke about an hour before daybreak on the 

 morning of Nov, 13, 1833, it being then dark, with the 

 exception of the stars (the moon then about two days old), 

 I was surprised to find a constant flashing of light in my 

 room, as if from the flickering of a dying lamp, or from 

 faint flashes of lightning, and, as the window-blinds were 

 dowu, I arose and went to one of the windows to ascertain 

 the cause ; when, lifting up the blind, I was astouished to 

 find it literally raining fire, coming down like a smart 

 shower of saow, or rather hail I immediately roused the 

 whole of my family to witness the phenomenon, and then, 

 throwing on a few clothes, hurried out of doors to observe 

 this great event more minutely. Upon going out and 



