EARTH. 170 
•T the fame fort. You look upon fuch concretions as 
being inexplicable by any other caufe than “ If it 
is, (you fay, p. 230,) by means of heat and fufon that the 
loofe and porous ftruffure of Jlrata (hall be fuppofed to 
have been confolidated, then every difficulty ... is at once 
removed. The loofe and difcontinuous body of a Jlratun 
may be clofed by means of foftnefs and comprejfon .” I have 
found a great variety of thofe groups in their naturalJtua- 
tion, and among thefe the puddingfones you mention ; 
and I will defcribe their general characters. The groups 
properly calied puddingflone by lapidaries, are found in 
loofe gravelly Jlrata of pebbles, fuch as compofe them ; 
and they only differ from the reft of the Jfatum, by the 
fund being concreted in that particular mafs. Similar con- 
crelions, but not worth the attention of lapidaries, are 
found in the Jlrata of the common flinty gravel ; and nei¬ 
ther in thefe, nor in the former, is there any fign of com¬ 
prejjion upon foft materials: the gravel of which they are 
formed has its natural fliape. The general caufe of fuch 
diftinft groups in loofe Jlrata, is the covfolidation of the 
fund between larger materials; which fand, from the be¬ 
ginning of the fratvm, filled up the interftices between 
?hofe materials. I have feen, in various countries, hills 
formed of loofe /and, in which were Jlrata almoft entirely 
eompofed of fea Jkells, mixed with fand; and in thefe 
Jlrata I have found pudding-J'ones formed of thofe Jells- in- 
‘ftead of gravel-, the fand between them was concreted. 
In other /andJlrata, where concretions have been only pro¬ 
duced between or round fcattered Jbeil's, I have found 
many fuch groups, in which the Jkells ftill retained their 
native colour. Laftly, I have feen, in Jlrata of gravel 
mixed with Jkells, pudding-Jone containing thefe two forts 
of bodies ; and the Jkells alfo had their native colours. 
All thefe fads are fo contrary to fuppofitions of heat, 
fufon, and foftnefs, that I am fure you would never have 
formed your hypothefis, had you had more opportuni¬ 
ties of ftudying, in their natural pojition, the fpecimens 
you have in your cabinet. The fea Jhells, mentioned in 
many of the above examples, lead me to a more general 
objection againft your hypothefis. It would be fufficient 
to examine thofe bodies, to be convinced, that the con¬ 
cretions in which they are found did not undergo a melt¬ 
ing-heat ; but, moreover, bow could you conceive, that 
the animals themfelves, of which thefe are the relitls, 
could have lived upon thefe very Jlrata, which you fup- 
pofe to have been fucceffively confolidated by fufion? Here 
ends every appearance of poffibiiity: and 1 might have 
confined myfelf to this Tingle objection, had I not thought 
it more convenient, to follow all the arguments you have 
adduced in favour of your own hypothefis. 
Since the ftrata of our continents have not been confoli- 
dated by fire, it muft be by feme procefs of zuater ; for 
you agree that their confolidation muft have been the effeCt 
of one of thofe two caufes: but you objeCt againft the 
laft, and I muft now examine your objections. We have 
feen that it is fufficient for the confolidation of loofe mate¬ 
rials, that any vehicle can help minute particles to infert 
themielves between larger ones, fo as to multiply the 
points of dole contaEl in the mafs; and water is fit for 
that purpole, Againft this you allege, p. 227, firft, the 
difficulty of finding corfolidating matters; and that alfo, 
of explaining, “ whence came the matter with which the 
numberlefs cavities in thofe maffes w'ere to be filled.” I 
fliall anfwer to thefe difficulties by a faCt. If we take 
proper lime and fand, we produce mortar-, if we mix it 
with Jones, we form a wall: if this be built in a place 
®liat (hall be afterwards covered with water, it will in 
time conjolidate , not only as well as in the air, but better. 
Now, fir, if your firft objection, that of. finding confo/i- 
dating matters, relates to lime f one, fandf one, or other ho¬ 
mogeneous folid Jrata, I anfwer, that thofe matters were 
originally in the Jrata themfelves, as they are in mortar ; 
and if. you fpeak of Jrata eompofed of diftinCt large ma¬ 
terials, with other iubftances between them, as Jrata of 
granite, pudding-flone, or of feme broken hard bodies now 
confolidated together, thefe Jrata have been confolidated. 
as walls, becatife of the intervals between the large ma¬ 
terials being filled with other fubftances which could 
conjolidate. Here, fir, there is a circumftance which is 
again decifive between your theory and mine. In yours, 
where fufion is to be the conjolidating caufe, it is impoffible 
to conceive, that Jrata of limefonc could be found upon 
loofe marie ; or JandJone and petrojlex, upon loofe fand ; 
which, however, is common: for, how could the upper- 
moft Jrata be melted, while thofe under them remained 
unaltered ? but that faCt is eafily explained in my theory ; 
for, as improper mortar would not conjolidate in water, fo 
all our Jrata which did not contain proper particles for 
their confolidation in the bottom of the fea, remain loofe, 
either wholly, or in part. 
You fay again, p. 227, “ Without fome power by which 
water .... fiiould befeparated .... it is inconceivable 
how thofe mafl’es (our Jlrata) fhould be abfolutely confo¬ 
lidated without a particle of fluid water in their compcfi- 
tion.” You are ntiftaken, fir; the moft part of our ftrata 
are ftill capable of imbibing water, in the fame manner as 
they contained it when they were confolidated ; as does 
mortar, either confolidated in water or in the air : and we 
have in the JalaElites, and in concretions made in water, in- 
ftances of more compaCt bodies confolidated in that man¬ 
ner. But another of your objections will bring 11s to a 
difquifition of greater importance: it is at p. 228, where 
yon fay, “ If water has been the merfiruum by which tire 
conjolidating matter was introduced into the interftices of 
Jrata, malles of thofe bodies could only be found confoli¬ 
dated with fuch fubftances as water is capable of diffolv- 
ing.” This argument is again contradicted by mortar 
and plajer ; which, though confolidated by the medium of 
water, are not Joluble in it : but I fliall now take a larger 
field, and maintain, not only the precipitation of conjoli- 
dating fubftances, but that of the whole of our Jrata 
themfelves; and, firft, of what water do you mean to 
fpeak: is it dijilled water, rain-water, or any particular 
Jpring-water ? Here you have already fome forts of waters, 
different in their faculty of diffolving -. but, in general, 
what are all our menfrua, if not water impregnated with 
fuch fubftances as make it capable of diffolving certain 
other fubftances? and how fhort is our knowledge of the 
power of nature, in refpeCi: of the compofition of menfrua, 
by previous folutions in that primary liquid, which is 
common to every menjruum? 
To prove fo you the neceffity of having recourfe to 
precipitation for the explanation of our Jrata, I fliall begin 
by pointing out the chafm you have left in your theory, 
by too fuperficial an examination of our continents. They 
are entirely formed of Jrata: confequently that fort of 
compofition muft have a common general origin ; and to 
difeover this, our attention muft be firft fixed upon the 
lowermoft of iheizJrata. However, you fay,p. 256, “The 
nature of granite is too intricate a fubject to be confider- 
ed where we have only to prove the fufon of fubftances 
from the evident marks which are to be obferved in a 
body.” This,is not applicable to granite, which furely 
bears no mark of fufon: and, in the mean time, it is the 
opinion of the moft informed naturalifts, that granite, or 
fome other fuch hard rock, forms the low ermoft Jrata 
of our continents. Perhaps that clafs of ftrata has the 
more embarraffed you, becaufe of a very important cir¬ 
cumftance, viz. that thofe lowermoft Jrata contain no re¬ 
licts of marine animals: but immediately above the Jrata 
of granite, there is an immenfe mafs of other Jrata, alfo 
without marine bodies : thefe are formed of grey rock, in¬ 
termixed with the (hivering Jrata of fchijus. What then 
became of the animals of a former fea, during the accumu¬ 
lation of thofe fubftances in their future abode? Whence 
came the materials of thofe two primary fets of did inti 
Jrata, fo generally fpread at the bottom of the ancient 
ocean ? Why did their, fo different, fubftances, come at 
diftinft periods ? Where was the fire kindled, that confo¬ 
lidated them, before the exiftence of the ftrata accumu- 
v lated 
