376 "MARLS" NOT CALCAREOUS. 



marl of Barton, <m the opposite side of the Trent though somewhat of a 

 similar coiitextui o, but of a darker, more dusky colour is in a manner 

 destitute of calcareosity ! one hundred grains of it yielding little more than 

 one grain not two grains of calcareous matter. Nevertheless, the pit, from 

 which I took the specimens analyzed, is an immense excavation, out of 

 which many thousand loads have been taken. And the marls of this 

 neighbourhood (which mostly differ in appearance from those described, 

 having generally that of a blood-red clay, interlayered, and sometimes in- 

 termingled with a white gritty substance) are equally poor in calcareosity. 

 One hundred grains of the marl of Stafford (which I believe may be taken 

 as a fair specimen of the red clays of this quarter of the district) afford 

 little more than two grains of calcareous matter lodged not in the sub- 

 stance of the clay, but in its natural cracks, or fissures. Yet this is said 

 to be 'famous marl;' and from the pits which now appear, has been laid 

 on in great abundance. 



" I do not mean to intimate, that these clays are altogether destitute of 

 fertilizing properties, on their first application. It is not likely that the 

 large pits which abound in almost every part of the district, and which 

 must have been formed at a very great expense, should have been dug, 

 without their contents being productive of some evidently, or at least ap- 

 parently good effect, on the lands on which they have been spread. I con- 

 fess, however, that this is but conjecture ; and it may be, that the good 

 effeet of the marls first described being experienced, the fashion was set ; 

 and the distinguishing quality being unknown, or not attended to, marls 

 and clays were indiscriminately used." -Marshall's Midland Counties, vol. 

 i. p. 152. 



8. "On the southern banks of the Anker, is found a gray marl; re- 

 sembling in general appearance the marl of Norfolk, or rather the fuller's 

 earth of Surrey. In contexture it is loose and friable. This earth is sin- 

 gularly prodigal of its calcareosity. The acid being dropped on its surface, 

 it flies into bubbles as the Norfolk marl. This circumstance, added to that 

 of a striking improvement, which I was shown as being effected by this 

 earth, led me to imagine that it was of quality similar to the marls of 

 Norfolk. But, from the results of two experiments one of them made 

 with granules formed by the weather, and collected on the site of improve- 

 ment, the other with a specimen taken from the pit, it appears that one 

 hundred grains of this earth contain no more than six grains of calcareous 

 matter ! the residuum a cream-coloured saponaceous clay, with a small 

 proportion of coarse sand." Marshall's Midland Counties, vol. i. p. 155. 



In the latter quotations are presented separately the proofs from 

 authors fully competent to try and know the remarkable facts 

 stated of many well approved " marls," so called, being nearly or 

 entirely destitute of calcareous earth ! I will now go bi. ,- 

 to older writers, who treat of marls without noticing that ingredient 

 as being present, or without seeming to be aware that its presence 

 would be useful. 



The learned and also practical Miller thus defines and describes 

 marl, in the Abridgment of the Gardener's Dictionary, fifth Lon- 

 don edition, 1763, at the article marl : 



" Marl is a kind of clay which is become fatter and of a more enriching 

 quality, by a better fermentation, and by its having lain so deep in the 

 earth as not to have spent or weakened its fertilizing quality by any pro- 

 duct. 



