intrusion of the basalt that they have assvimcl a cohnnnar structure like tlje basalt 
itself, and may readily be mistaken for a section of the VViiin Sill. The river 
continues its rapid course, and between Cauldron Snout and the junction of the 
Lune — the most Westerly and Easterly points of investigation — in a distance of ii 
miles there is a drop in level of 800 feet. The area marked out is a portion of the 
eastern Hank of the Pennine range, and in the western part occurs the thickest 
section of the Whin Sill — a dolerite rock generally regarded a? intrusive, although 
there are authorities who contend for a submarine overflow. The beds above and 
befow the sill give the whole series of the \'oredales, many of which the members 
will have excellent opportunities of examining, and between Lunedale and Teesdale 
they attain their highest point of elevatibn. At White Force, on Cronkley Scars, 
the waterfall is over the Whin, and in wet weather is very picturesque, but its chief 
attraction to the geologist is the limestone base, wliich has been altered by contact 
wnth the Whin, and is now of saccharoidal character for a thickness of 30 or 40 feet, 
the M liole of which is accessible. The grain is much finer than that found in 
Widdy Bank. 
The whole district is full of mineral veins. Lead has been largely worked. 
Zinc blend is visible, and Baryta is now worked. There ate several very marked 
faults, one, the Teesdale fault — determining the course of the river for some miles — 
has a down-throw to the north, and another in Lunedale has a down-throw to the 
south, leaving an elevated region in between the two. The great Burtreeford Dyke, 
which extends from Wearhead in Durham to Cronkley Fell, can be seen where it 
crosses the Tees, and gives excellent opportunities for examining th.e disturbance of 
the strata. 
VERTEBRATE ZOOLOGY— The Vertebrate Section will be (;fticially 
represented, 
BIRDS. — Man}- rare birds frequent Upper Teesdale, for particulars see Mr. 
James Backhouse's " Upper Teesdale." 
Mr. W. Walton, of Middleton, will join the party and give assistance to the 
ornithologists. 
CONCHOLOGY.—The Conchological Section will be officially represented 
BOTANY. — This Section will be officially represented by Dr. W. G. Smith, 
of Edinburgh. 
The district is rich botanically. For particulars see Baker's "North York- 
shire," and the chapter on Teesdale Flora, by Mr. James Backhouse, in " Upper 
Teesdale." 
Mosses aiid Hepatics. — The Yorkshire Bryological Committee will be 
officially represented by Mr. W. Ingham, who w-rites : — This is a very rich district 
for these plants, and there are numerous interesting records by Spruce and many 
other botanists, far too many to indicate in this circular. 
The following are plants of interest recorded during the last few years, most of 
them by the writer. 
Widdy Bank seems too far from ^^iddleton as a centre, so its many rareties 
are omitted. 
L Hepatics — -On Holwick Fell. — Lophozia FloerkU, L. Lyoni^ L. barbaia^ 
Aplozia cordifolia, and Plaf^iochila spinulosa, a large form in fruit (the last in Fairy 
Dell). At the High Force, Reboulia hernispharica^ Madoiheca Icevigata, M. Hvu- 
laris, and Aplozia lordifolia. Between Winch Bridge and High Force, Scapania 
rosacea, S. icqniloba. At the White Force, Preissia quadrata^ Me/zgeria pubescenSy 
Marsupella Fearsoii, M. aqica/ifa, Lophozia hantrieiisiss Eiicalyx obovata, and 
Plagiochila Dillenii. 
IL Sphagna. — The richest ground for these is Cronkley Pastures, between 
Cronkley Scars and the R. Tees, where most of the British species of Sphagna are 
to be found. The rarest are : — .S". Girgensohnii with vars, commmie, coryp/iceum, 
crisiafiun, hydrophilum, spectabile^ stachyodes, and xerophilum ; S. Rtiswivii vars. 
rhodochroiivi^ and viresceus ; S. IVarnstorfii on Cronkley Fell ; S. Rubelhim vars, 
paUes^cens, purpttrascem^ rubrum, versicolor and viridt on Cronkley Fell ; and the 
last var. also in the Pastures ; S. fuscHm on the I'ell ; .V. qtiinqjiefariurn vars. 
palUsceits, rosenm, and virescens m the Pastures, and v. fusco-flarJUfn at the Whiter 
Force ; S. Ures, pannfolinni^ S. medium v. z>t)sicolor on Cronkley Fell. 
