SCIENTIFIC NEWS. 
Tliesc specimens formed part of a bod of rubble, covering 
the summit of a hillock of grey, or the lower chalk, about five 
miles S. \V. of Cambridge. This hillock, like several others 
in the same county, is situated to the west of the great rani,e 
of chalk, being surrounded by the blue marl or gault, as it is 
provincially termed, from which the overlying bed of oJialk 
is separated by a thin bed of green sand. The rubble, besides, 
coDsisliug of chalk and flint, also contains shelllimestonc, an- 
gular pieces of green stoue, and certain organic remains Irelong- 
iog to older beds than the chalk ; but ns all these beds bas.set 
more or less to the w’cst of the place where these fragments 
are now to be found, the circumstance is considered by ^Ir. 
Warburton as indicating an ancient current, the course of wlitch 
was from west to east. 
A paper eatilJed, “ Observatious on Glen Tilt,'* by Dr. 
Mac Cullotd), V..P. G. S. was also read. f • < . ^ ■ 
That part of Glen Tdt, which G the subjt'Ct of tho proseitf 
paper, extends fimr or five miks from Forest Lodge ta Gow'a 
Bridge. Jt, cousins of primitive sdust,: assuming Ylie appeases 
ance of clay, of mica slau‘, bnd of boriubleoiia skitei wrlhl 
which arc iniefstratified various beds of > graiuflsn JimMq>n» 
luwe or less micaceous. K cat Qow'» bridge ihc^'slrat’lTcaiMni 
$ 
ts perfectly rc^plttr and uninternupted, but bighei^ npt tow.tnfa 
the Lodge, it its traversed* by gjanitr* irook^-^and adcirslkirte 
multitude of granite \eius of variousi sixesjl Wiiesa rbts^amn 
rock, makes its apiHiarance, the even cr'urse of tbe> ^cllilltlsMiv 
interrupted iii^Hupoition to, the ooiagnilade of the avass. of'mH 
nlte. When the granite, schi.it, . and limeitofnfe ar» aty ia^jon- 
lact, a perfect, confusion of these three substances uak n: Ipface. 
Where the granite and limestone are in contact, >tlie latter is 
highly indurated, and penetrated by siHcaous mattert 
» - 
* 
Appendix. Vol. XXXVT.-— No 170. 
Ff 
The 
