106 



FARMERS' REGISTER. 



[No. 2 



the constituents of blue marl, well worth the in- 

 quiries of your Proitissor Roifers, and our Pro- 

 fessor Ducalel, botli state geolo;iist8. VVhntsaia- 

 ly Prolessor Rogers receives trom your state I tlo 

 not know ; but Prolessor Ducatel's from ours, is 

 fully adequate, and I think, the inquiry within the 

 scope of his duties. Rusxicus. 



E. S., iMarylaiid, Feb. 1st, 1839. 



[The supposition of our correspondent, as to 

 there being some other useful ingredient than 

 the calcareous part, in blue marl, is doubtless cor- 

 rect. But whether the additional value thence 

 derived is enough to be appreciated, is more than 

 we can say. The observation of the particular 

 facts, which will be stated in the following article, 

 first pointed out to us, and satisfactorily, that it 

 was the dark colored extract of vegetable matters 

 which gave the blue color to shell-marl. And 

 this coloring matter is undoubtedly chem.ically com- 

 bined with the calcareous matter, and cannot be 

 removed by any washing with pure water. The 

 proof of this is, that in all the pits dug into the 

 very remarkable blue marl, described below, on 

 Shellbanks (arm, water, in great quantity, passed 

 through every part of the mass, without there be- 

 in-; the slightest effect produced in lessening the 

 deep tint ol the marl, or affecting the purity ol the 

 water. Further — in the well dug through this 

 bed of marl, and which received its principal sup- 

 ply ol" water from a soft quick- sand beneath, the 

 water rose to and stood at the height of about 13 

 feer, and altogether in this blue- marl. Yet the 

 water was at first, and has continued to be, re- 

 markable for its purity and excellence. 



The Ibilowing statement was written to form a 

 part of the second edition of the 'Essay on Cal- 

 careous Maruires,' and was one of several por- 

 tions omitted, because it was desired to include 

 nothing that was extraneous, or not sufficiently 

 sustained by iiict, or reasoning. But though no 

 similar particular observations have since been 

 made, nor any experiment tried, it is proper here 

 to state that nothing has been since learned to 

 cause doubt of the then supposed cause of the co- 

 lor of blue marl; and that the time which has 

 elapsed, and general observation, have confirm- 

 ed, what then was doubtful, merely because 

 new. — Ed. Far. Reg. 



THE ni^UE COLOR OF MAUL PROBABLY CAUS- 

 ED BY THE PRESkUNCE OF VEGKTABLK MAT- 

 TER. 



[An omitted note, written for tlie 'Essay on Calcareous 

 Manures.'] 



A fact which has very recently fallen under my 

 observations, seems to throw liglit on the cause of 

 the blue color of some marls. I will, however, 

 merely state the facts, and leave it to others to 

 reason as to the causes. 



There is one body ofmarl at Sliellbaiiks of very 

 unco(nmon appearance. The upper part is dry 



and yellowish, soft, and as fine and even more 

 yielding than sand ; which is similar at the topa 

 of many other beds. Below, it is wet and firm, 

 but still yellow ibr some six to ten inches. Still 

 lower, and without any perceptible change of tex- 

 ture, there is a sudden change of color, precisely 

 to a line, (though not quite a horizontal line,) to 

 a deep and beautiful sky-blue; by lar the most 

 pertect blue known in marl or earth of any kind. 

 This color continues to the bottom; as was known 

 by having dug a well through it at a few hundred 

 yards distance. Beneath the marl, there is a 

 brownish quick sand, from which an abundance 

 of pure water rose. It may be well to observe 

 here, that whenever marl is blue, there is no 

 other color known beneath ; and it certainly waa 

 the lowest in two other remote bodies, through 

 which I reached the bottom, on another farm. 

 The bottom of this bed (at Shellbanks,) could not 

 be reached, except in the well, though many pits 

 were dug 6 to 7 Icjet deep in the blue marl. The 

 whole of this wet marl, (yellow as well as blue,) 

 consists of alternate thin layers of a fine and close 

 calcareous clay, (apparently the true marl of min- 

 eralogists,) and of finely broken fragments of shells, 

 few of which are larger than grains ol" wheat, and 

 generally much smaller. The layers of clay vary 

 Irom ooe-eigluh to half an inch in thickness, 

 and the layers of powdered shells fill l"roni double 

 to triple these difierent spaces. The digging is on 

 the edge of an alluvial fiat, which above is a wet 

 swamp ; and a stream passes by the marl, and 

 nearly as hi<j;h as it is wet. In digging pits, the 

 water passed so last through the porous layers of 

 broken shells, and from every side, that it was very 

 difficult to sink the digging even to 6 or 7 Itjet ; and 

 to get to that depth, there were, towards the last, 

 two men kept constantly throwing out water to 

 enable two others to dig and throw out marl. 



From another body, about 400 yards distant, 

 which was of different appearance, and showed 

 no blue color, even at the lowest known depth, 

 where also it was wet, some of the upper dry and 

 fine part was taken in 1833, to floor a stable yard, 

 for the purpose of absorbing and saving the li- 

 quid manure. The marl was covered with vege- 

 table and animal manure, and sometimes with 

 such filth from about the houses, as well as the 

 cleanings of the stable. About 12 months after it 

 had been so placed, this once yellow marl was 

 dug into, and found to present the same deep and 

 beautiful blue color of" the former body described. 



THE LAST COMMUNICATIONS OF GEORGE E. 

 HARRISON, OF BRANDON. 



The following communications were prepared 

 just before the sudden illness which resulted in 

 the death of the writer, only five days after the 

 date of liis letter ; which event deprived the coun- 

 try of one of" its most useful and valuable citizens. 

 We speak of George E. Harrison solely as an im- 

 prover and cultivatorof the soil — in which respects 

 his labors were among the most beneficial to the 

 agricultural interests of Virginia, of all such that 

 have been performed. It does not comport with 

 the design of this publication to remark on other 



