590 



SCIENCE. 



[Vol. IX., No. 228 



The rugged islands of Laurentian and Huronian 

 rocks correspond in both regions, and show an iden- 

 tity of succession in deposits as well as a synchro- 

 nism of the great folds and lateral pressures which 

 have disturbed these old formations on both sides of 

 the Atlantic. The Cambrian sediments and fossils 

 as originally described by Hartt, and more recently 

 and in so great detail by Matthew, are in close corre- 

 spondence with those of Wales, and not identical 

 with those of internal America. The recent paper of 

 Lapworth on the graj)tolites affords evidence of the 

 same kind, and shows that these were Atlantic ani- 

 mals in their time. It also throws much additional 

 light on the Quebec group of Logan, considered 

 as an Atlantic marginal formation, representing a 

 great lapse of time in the Cambrian and Ordovician 

 periods. The author had long ago shown that the 

 Siluro-Cambrian or Ordovician of Nova Scotia con- 

 formed more nearlj' to that of Cumberland and 

 "Wales than to the great limestone formations of 

 Quebec, Ontario, and New York. The upper Si- 

 lurian also is of the type of that of England and 

 "Wales, — a fact very marked in its fossil remains as 

 well as in its sediments. 



The parallelism in the Erian or Devonian in both 

 countries is most marked, both in rocks and fossils ; 

 and, while this is apparent in the fishes as worked up 

 by Mr. Whiteaves, it is no less manifest in the fossil 

 plants as described by the author. 



The carboniferous, in its limited troughs, the 

 character of its beds, and its fossil animals and 

 plants, also points to a closer relationship in that 

 period between the two shores of the Atlantic than 

 between the Atlantic coast and the inland area. 

 This was evidenced bj^ comparative lists of species. 



The trias of Nova Scotia and of Prince Edward 

 Island, as the author had shown in 1868 {Joif^rn. 

 geol. soc. Lond.), resembles that of England very 

 closely in its aqueous deposits and in its associated 

 trappean rocks. 



Beyond this, the geology of the maritime prov- 

 inces presents no materials for comparison till we ar- 

 rive at the bowlder drift and other pleistocene de- 

 posits. In regard to these, without entering into 

 disputed questions any further than to say that 

 the observations of the author, as well as those more 

 recently made by Mr. Chalmers, conclusively proved 

 that submergence and local ice-drift were dominant 

 as causes of distribution of bowlders and other 

 material, there was evidence of great similarity. The 

 marine beds described by Mr. Matthew at St. John 

 were precise equivalents of the Clyde beds of Scot- 

 land, as were the upper shell-bearing beds of Prince 

 Edward Island and Bay de Chaleur of those in Aber- 

 deenshire and other parts of Scotland, and the Ud- 

 devalla beds of Sweden. The bowlders drifted from 

 Labrador to Nova Scotia were the representatives of 

 those in Europe scattered southward from Scan- 

 dinavia, and the local drift in various directions 

 from the hills was the counterpart of that observed 

 in Great Britain. The survival of Mastodon gigan- 

 teus in Cape Breton, to the close of the pleistocene, 

 is a decided American feature, and so is the absence 

 of any evidence of pleistocene man. 



The conclusion of the author was, that, in so 

 far as paleontology and the subdivisions of systems 

 of formations are concerned, the geology of the 

 maritime provinces is European, or perhaps more 

 properly Atlantic, rather than American, and is to be 

 correlated rather with the British Islands and Scan- 



dinavia than with interior Canada and the United 

 States. The latter country, even on its eastern 

 coast, possesses a much less perfect representation 

 of these Atlantic deposits than that in the maritime 

 provinces and Newfoundland ; though the recent 

 studies of Crosby, Dale, and others are developing 

 new points of this kind in the geology of New 

 England, and Hitchcock and others have shown 

 that the New Brunswick geology extends into Maine. 

 The paper further discussed the bearing of these 

 facts on the successive stages of the physical geogra- 

 phy of eastern America in the Cambrian, Silurian, 

 Erian, carboniferoiis, and triassic records. 



J. Wm. Dawson. 

 Montreal, May 30. 



Sea-sickness. 



In Science for June 3, I find a very interesting re- 

 view of the medical literature of this subject. It is 

 but natural that means, both XDrophylactic and cura- 

 tive, should be sought for the benefit of those who 

 find a sea-voyage one of torment rather than pleas- 

 ure ; and the writer has frequently thought that some 

 stiggestions derived from the otologist's experience 

 might not be without interest in this connection. 

 Thus, in a considerable experience among persons 

 suffering from aural disease, it has been found that 

 vertiginous symptoms are of frequent occurrence ; 

 that the phenomena, in fact, which constitute what 

 is known as ' sea-sickness,' are by no means exclu- 

 sively experienced by the comparatively few who sub- 

 mit to being tossed about at sea. Indeed, as every one 

 familiar with the subject very well knows, most of 

 the symptoms going to make up this malady are 

 found, in some form or other, to render the lives of 

 a great many persons living upon terra firma raost 

 miserable. A great many of these individuals ex- 

 perience almost daily, frequently much oftener, sea- 

 sickness without ever going on board ship. The 

 sufferings of these seem to be owing to a faulty con- 

 dition of the transmitting mechanism of the ear, — de- 

 fects in respect to which it may be said, that, when 

 normal tension of this portion of the hearing-organ 

 is thus wanting, nearly all the symptoms of sea-sick- 

 ness may take place from slight though altogether 

 unavoidable, constantly occurring caixses. Persons 

 thus affected cannot rise up suddenly from a recum- 

 bent position, or otherwise change the pose of the 

 head, without feeling dizzy or staggering when at- 

 tempting locomotion. Sometimes they experience 

 nausea, and feel faint and otherwise miserable. Or 

 the mere acts of swallowing, yawning, or hiccough- 

 ing, whereby intra-tympanal aeration is suddenly 

 altered, may be followed by distressing and some- 

 times alarming symptoms. The experience of ver- 

 tiginous phenomena in some form or other, closely 

 simulating what is known as 'sea-sickness,' like- 

 wise occurs to the aurally defective in consequence 

 of cerebral concussion caused by impacts of the 

 stapes upon the fluid in the labyrinth, and arising 

 from oscillatory movements of the drum-head when 

 its functions are no longer under the dominance of 

 normal tension. The erratic drum-head, flapping in 

 response to sudden movements of the head, acts of 

 swallowing, etc., would seem to force the stapes 

 into and out of the oval window to an extent far ex- 

 ceeding its physiological limits ; and, thus jostled 

 about, the stapes, with each excursion of the drum- 

 head, imparts a shock to the labyrinthine fluid. I 

 am aware that it has long been held by physiologists 



