566 



NA TURE 



[April i r, 1901 



may have desired to cultivate their woods on scientific 

 principles may have met with the difficulty of obtaining 

 expert advice ; but such a difficulty no longer exists, for 

 there are in this country now retired forest-officers of the 

 Indian service to whom proprietors may readily go for 

 ^ound and safe guidance. At the same time we cannot 

 hope that the cultivation of crops of timber in this 

 country will attain the dimensions which it must do if 

 it is to affect to an appreciable extent the market supply 

 of timber until means for the acquisition of knowledge 

 of scientific principles underlying it are available to those 

 to whom woods belong and to those who have the direct 

 management of the woods. Within the last decade 

 several trustworthy text-books upon forestry have ap- 

 peared, but our only school for instruction in forestry at 

 the present time is that at Coopers Hill. Coopers Hill 

 is, however, open only to entrants to the Indian Forest 

 Service, and there is no institution in the country to 

 which any one desiring a thorough acquaintance with 

 the principles of forestry can go. Our Universities are 

 now alive to the claims of agriculture as a subject of 

 study, and agricultural colleges are being formed 

 -in different districts. How long will it be before the 

 Universities recognise that forestry also is worthy of 

 attention, or the agricultural colleges take up the subject 

 in their curricula ? It is matter of common knowledge 

 that a committee appointed by the Secretary of State for 

 India recently reported in favour of the transference to 

 Cambridge of the forest-school from Coopers Hill. As 

 yet, however, no action has been taken upon the recom- 

 mendation. The Secretary of State may rest assured 

 that such a transference would be a reform meeting 

 with the hearty approval of men of science, and the 

 presence at Cambridge of such a school would give an 

 opportunity to undergraduates connected with the landed 

 interest to obtain some acquaintance with a subject of 

 intimate concern to them. The influence of this upon 

 the prosperity of the country would ultimately be most 

 beneficial. As has been said above, ignorance is the real 

 cause of our present condition as a wood-growing country, 

 and until systematic instruction is provided in some of 

 our Universities or colleges there will be no great re- 

 formation in forestry practice, althoagh there may be 

 amelioration through the action of intelligent and far- 

 seeing individual proprietors. 



THE CONCRETIONS OF THE CONNECTICUT 

 VALLEY} 



THE curiously-shaped concretions met with in the 

 Champlain clays of the Connecticut Valley have for 

 many years attracted attention. Indeed, so long ago as 

 1670 some specimens were sent to the Royal Society of 

 London. A detailed description of them and of their 

 mode of occurrence, illustrated by fourteen beautiful 

 quarto plates, has now been issued by Mr. J. M. Arms 

 Sheldon. Four principal types of concretions are met 

 with ; some are discs which call to mind the Kimeridge 

 coal-money ; some are cylindrical or club-like, one 

 example (probably a compound one) being a little more 

 than twenty-two inches long ; others are botryoidal, and 

 not a few are " queer little images" resembling "fishes, 

 birds, ant-eaters, elephants, dogs, babies' feet," &c. (Fig. i). 

 These occur in stratified river-drift clays, some of which 

 are of a kind suitable for modelling, and some are more 

 or less gritty. The most remarkable point is that " each 

 clay bed has a form of concretion peculiar to itself," that 

 is to say, the principal types are never found together. 

 The author has seen " forty-eight specimens from one 

 bed so similar it was impossible to tell one from another." 



1 " Concretions from the Champlain Clays of the Connecticut Valley." 

 4to. (Boston, 1900 ) 



Compound forms occur, where, for instance, two or even 

 three discs have coalesced or been joined together (Fig. 2) ; 

 and intermediate stages of such examples, and of immature 

 concretions of horse-shoe type, are met with. 



These remarkable bodies occur along the planes of 

 bedding in the clays, and the lines of stratification may 

 sometimes be seen to run in unbroken continuity through 

 concretion and clay. In composition they consist of 

 argillaceous and somewhat sandy limestone with small 

 amounts of iron-oxide, magnesia and manganese oxide. 

 They contain from 42 to 56 per cent, of carbonate of 

 lime, whereas the clay possesses but 2 or 3 per cent. 

 The concretions spread out laterally in the clay, as if 

 water holding carbonate of lime in solution made its way 



Fig. I. — An animal form cf concretion. * 



along the planes of stratification ; and unless in the case 

 of tiny spheroidal concretions they are almost invariably 

 flattened. No doubt they are due to the obscure process 

 of segregation, whereby the mineral matter, tending to 

 collect together, has been unable to assume definite 

 crystallographic shape, but has concentrated itself in 

 nodular form. Some of the concretions show evidence 

 of concentric structure, but no appreciable nucleus has, as 

 a rule, been seen, though it might have consisted of a 

 particle of carbonate of lime. Evidently the concre- 

 tionary process went on in a quiet way, but not always 

 uninterruptedly, as indicated by the distinct stages of 

 growth seen in some specimens. The shape of the con- 

 cretions is held to be partly determined by the structure 



NO. 1641, VOL. 63] 



Fig. 2. — A treble form of symmetrical concretion. 



and composition of the matrix which holds it, and by 

 the amount of carbon dioxide and other organic acids 

 present. 



The author concludes his work with a useful biblio- 

 graphy, wherein the well-known researches of De la 

 Beche, and the observations of A. H. Green and others 

 are mentioned ; but we miss the name of Sedgwick, who, 

 in 1835, brought the matterbefore the Geological Society 

 of London. The author, however, does not enter into 

 the general question of concretionary structures ; his work 

 is essentially local, but it will be none the less interesting 

 to those who give attention to the subject. 



H. B. W. 



