6 



SCIENCE. 



he believes that the cave was supplied at a time when this 

 region was a salt or brackish water estuary. Prof. Put- 

 nam therefore concludes that the blindness of these fish 

 has been in no respect a consequence of subterranean 

 life. 



Discussion. 



Mr. Britton inquired whether any flora existed in 

 the cave. 



Mr. Stevens replied that, so far as he was aware, no 

 kind of vegetation had ever been found within it. 



Dr. Newberry remarked on the geology of the region 

 adjacent to the Mammoth Cave. The limestone beds of 

 this high table-land are jointed in the manner common 

 to rocks, apparently by some sort of polarisation, produc- 

 ing fissures which run in a north and south, and an east 

 and west, direction. The plateau is about 500 feet above 

 the drainage, part of the drainage passing into the Green 

 River, and part into the Ohio. No streams occur on the 

 surface and the drainage is quite gradual. At the angle 

 between these two rivers several streams are seen, burst- 

 ing out of the cliffs at various heights above the Ohio ; 

 they are, so to speak, subterranean sewers, representing 

 the underground drainage of the country ; at one point 

 three such streams pouring out of the rock form very 

 beautiful cascades ; and near Sandusky a full grown river 

 flows out of the cliff of cavernous limestone. The beds 

 consist of lower carboniferous limestone, with sandy layers 

 beneath. In the vicinity occur portions of the great " blue 

 grass region," one of the oldest parts of the continent, 

 once an extensive highland, forming an island in the sea. 

 Around this, rims of sediments were deposited, consisting 

 of sandstones and limestones ; while on the other hand, 

 the continuous process of erosion, during the lapse of a 

 vast period, removed the material of the table-land within, 

 and converted it into a broad depression or basin, the 

 " blue grass region," above which the present plateau of 

 the encircling sediments now rises to a height of 500 feet. 



The erosion of the joints in this plateau has resulted 

 in the formation of the pits described by Mr. Stevens, but 

 it is probable that some of these may reach 200 or 300 

 feet below the Ohio and Green Rivers. There is evidence, 

 from borings in the Delta of the Mississippi, etc., that 

 the Continent was formerly more elevated, standing 500 

 to 600 feet higher at New Orleans than at present ; the 

 drainage was much freer, the Mississippi being a free 

 flowing stream, as well as the Ohio and other tributaries. 

 Borings have been sunk in the present trough of the Ohio 

 river, to a depth of over 100 feet below its present bot- 

 tom, without reaching the true bottom of the trough, the 

 ancient bed of the river, which is perhaps from 100 to 200 

 feet further down. 



Evidences of the same elevation of the continent were 

 observed in caves on an island in Lake Erie. Long stal- 

 actites projected from the roof of a gallery whose end 

 was ordinarily filled with water at the present level of the 

 lake. At times a strong and steady wind has blown down 

 the level of the lake and partially drained this gallery ; but 

 even then a guide, John Brown, resident on the island, 

 has swum through the gallery and found the stalactites 

 projecting from the roof as far as he could go. 



In regard to the origin of the blind animals, the view of 

 Prof. Cope is probably correct, that they have been de- 

 rived from the degeneracy of ancestors who once had 

 perfect eyes. No fish is formed with poor eyes; but any 

 organ may be atrophied by disuse, with consequent feeble 

 flow of blood, decreased nutrition, and inevitable shrinking 

 of important parts. An analogy is shown in a comparison 

 of the jaws of prehistoric and modern men. At present 

 our " wisdom teeth " are useless, there is no room for 

 them in the shortened under-jaw ; our food being softened 

 by cooking, cut up, and boneless, requires less vigorous 

 mastication ; and from disuse, and the consequently in- 

 sufficient development, these teeth often speedily fall 

 away. In the prehistoric man, on the contrary, the jaws 



were longer, roomier, supplied with more teeth — the 

 " wisdom teeth " being well developed and kept in strength 

 by constant use on coarse and rough food. The absence 

 of the well-known stimulation produced by light, from the 

 dark waters within the Mammoth Cave, has in the same 

 way resulted in the atrophy of the organs of sight. 



CORRESPONDENCE. 



The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. No notice is taken of anonymous cornmuni 



cations.'] 



To the Editor of " Science." 



We can sympathize sincerely with the Editor of The 

 Popular Science Monthly in his indignation at being held 

 a promulgator of the views of "pronounced atheists," 

 because of his publication of " the papers of Herbert 

 Spencer, and others of his class." "Pronounced 

 atheism" finds little place in the history of philosophy 

 or science, as in the history of mankind and human civil- 

 ization in general. And Dr. Youmans is certainly in the 

 right with his emphatic denial that Mr. Herbert Spencer, 

 in particular, pronounces himself an atheist and seeks to 

 persuade others to do likewise. He "and others of his 

 class " have, indeed, been very out-spoken in questioning 

 the literal truth of many popular beliefs and sacred tra- 

 ditions. But that there is in " religious ideas" no "vital 

 element," that they correspond to no fact and represent 

 no truth, Mr. Spencer has been far from asserting. On 

 the contrary, the precise opposite is most strenuously 

 maintained by him (see especially Spencer's First Prin- 

 ciples, Part I.). 



And yet, while all this is verbally true, we fear that Dr. 

 Youmans, in his just zeal to defend himself and his friend, 

 both goes too far in his statement of the latter's real posi- 

 tion, and forgets those grounds which lend color of justi- 

 fication to the perfectly sincere supposition of many 

 thoughtful people, that the practical, if not the professed 

 or intended, tendency of Mr. Spencer's philosophy, is in 

 the direction of virtual atheism. 



If it were really true that " no man of the present age 

 has reasoned out the foundations of man's belief in the 

 existence of the ' Infinite and Eternal Spirit ' with such a 

 depth of analysis and logical force as Herbert Spencer," 

 if, as Dr. Youmans further declares, it were strictly true 

 that Mr. Spencer " has sought to show that the ' Infinite 

 and Eternal Spirit,' of which all the phenomena of the 

 universe are but manifestations, is the most absolute of 

 all realities," then religion would owe to him a debt of 

 gratitude, which it is inconceivable that the intelligent 

 defenders of religion should not gladly recognize and 

 avow. But we are at a loss to know on what grounds 

 the above assertions are made by the Editor of The 

 Popular Science Monthly. Perhaps it is in esoteric dis- 

 coveries, delivered to a select few of his admirers, that 

 Mr. Spencer has " reasoned out " the aforesaid " founda- 

 tions " and " sought to show " the pre-eminent absolute- 

 ness and reality of the ' Infinite and Eternal Spirit, ' and 

 Dr. Youmans's statements may have been made on the 

 basis of what he has personally been privileged to hear of 

 these discoveries, Thus the writer of these lines was once 

 informed by an admirer of Mr. Spencer's, who had recently 

 come from a personal interview with the philosopher, 

 that the latter believed in " a God " — supposing;, not with- 

 out a good deal of reason, that this would be a piece of 

 news to one who knew of Mr. Spencer and his opinions 

 only through his published writings. 



It is in the latter way, only, that Mr. Sfienccr is known 

 to the general public. We, for our part, cannot claim for 

 ourselves familiarity with every line which Mr.Spencer has 

 ever written. But we have studied with great care and 

 with great interest, what we supposed to be Mr. Spencer's 

 of the ledistribution of matter and motion. Some of 

 these phenomena have indeed a mysterious " obverse" 



