476 Reports and Proceedings — Prof. Green's Address. 



The reason, I think, is not far to seek. The imperfection of the Geological 

 Eecord is a phrase as true as it is hackneyed. No more striking instance of its 

 correctness can be found than that furnished by the well-known Mammalian jaws 

 from the Stonesfield slate. The first of these was unearthed about 1764 ; others, to 

 the number of some nine, between then and 1818. The rock in which these precious 

 relics of the beginning of Mammalian life occur has been quarried without inter- 

 mission ever since ; it has been ransacked by geologists and collectors without 

 number ; many of the quarrymen know a jaw when they see it, and are keenly 

 alive to the market value of a specimen ; but not more than six or seven of these 

 prized and eagerly-sought-after fossils have turned up during the last seventy years. 



Then again how many of the geological facts which we gather from observation 

 admit of diverse explanation. Take the case of Eozoon Cann dense. Here we have 

 structures which some of the highest authorities on the Foraminifera assure us are 

 the remains of an organism belonging to that order ; other naturalists, equally 

 entitled to a hearing, will have it that these structures are purely mineral aggregates 

 simulating organic forms. And hereby hangs the question whether the limestones 

 in which the problematical fossil occurs are organic, or formed in some other and 

 perhaps scarcely explicable way. 



And this after all is only one of the countless uncertainties that crowd the whole 

 subject of invertebrate palaeontology. In what a feeble light have we constantly 

 to grope our way when we attempt the naming of fossil Conchifers for instance. 

 The two species Gryphcea dilatata and G. bilobata furnish an illustration. Marked 

 forms are clearly separable, but it is easy to obtain a suite of specimens, even from 

 the Callovian of which the second species is said to be specially characteristic, 

 showing a gradual passage from one form into the other. And over and again the 

 distinctions relied upon for the discrimination of species must be pronounced far- 

 fetched and shadowy, and are, it is to be feared, often based upon points which are 

 of slender value for classificatory purposes. In the case of fossil plants the last 

 statement is notoriously true, and yet we are continually supplied with long lists of 

 species which every botanist knows to be words and nothing more, and zonal divisions 

 are based upon these bogus species and conclusions drawn from them. 



It is from data such as have been instanced, scrappy to the last degree, or from 

 facts capable of being interpreted in more than one way, or from determinations 

 shrouded in mist and obscurity, that we geologists have in a large number of cases 

 to draw our conclusions. Inferences based on such incomplete and shaky foundations 

 must necessarily be very largely hypothetical. That this is the character of a great 

 portion of the conclusions of geology we are all ready enough to allow with our 

 tongue — nay, even to lay stress upon the fact with penned or spoken emphasis. 

 But it is open to question whether this homage at the shrine of logic is in many 

 cases anything better than lip-service ; whether we take sufficiently to heart the 

 meaning of our protestations, and are always as alive as our words would imply to 

 the real nature of our inferences. 



A novice in trade, scrupulously honest, even morbidly conscientious to begin 

 with, if he lives among those who habitually use false scales, runs imminent risk 

 of having his sense of integrity unconsciously blunted and his moral standard 

 insensibly lowered. A similar danger besets the man whose life is occupied in 

 deducing tentative results from imperfectly ascertained facts. The living, day by 

 day, face to face with approximation and conjecture, must tend to breed an indif- 

 ference to accuracy and certainty, and to abate that caution and that wholesome 

 suspicion which make the wary reasoner look well to his foundations, and resolutely 

 refuse to sanction any superstructures, however pleasing to the eye, unless they are 

 firmly and securely based. 



If I am right in thinking that the mental health of the geologist of matured 

 experience and full-grown powers is liable to a disorder of the kind I have indicated, 

 how much greater must the risk be in the case of a youth, in whom the reasoning 

 faculty is only beginning to be developed, when he approaches the study of geology ! 

 And does it not seem at first sight that that study could scarcely be used with safety 

 as a tool to shape his mind, and so train his bent that he shall never even have 

 a wish to turn aside either to the right hand or to the left from the strait path that 

 leads through the domain of sound logic ? 



That it is hazardous, and that evil may result from an incautious use of geology 

 as an educational tool, I entertain no doubt. The same may indeed be said of many 



