SURVEY OF THE BRITISH ISLES FOR THE EPOCH JANUARY 1, 1891. 
Page. 
Nomenclature and Magnetic Contour Surface. 610 
Magnetic Ridge and Valley Lines, Peak.s, and Cols. 612 
General Results of tLe Surrey.. . 613 
Relative Importance of Magnetic Districts. . 613 
Secondary Ridge Lines. 614 
Methods of DraAving Ridge and Valley Lines. 615 
Magnetic Districts of the United Kingdom. 615 
(1) Tbe Great Glen, or Caledonian Canal District. 615 
(2) and (3) Cape Wrath and Loch Broome. 618 
(4) and (5) North and South Ahe^’deenshire. 619 
(6) Crieff. 020 
(7) The Scotch Coal Field and the Cheviots .... .. 621 
(8) GalloAvay. 624 
(9) The English Lakes. 625 
(10) Lincolnshire and Yorkshire .... 626 
(11) Derbyshire. 62S 
(12) North Wales. 029 
(13) Mid Wales. 630 
(14) Smrthern England and Wales. 630 
(15) The Bristol Channel. 632 
(16) Devonshire. 632 
(17) Cornwall. 632 
(18) Antrim. 633 
(19) Mid Ireland. 634 
(20) Wexford. 636 
(21) Fragmentary Coast Districts. 637 
On the Relation between the Magnetic and Geological Constitution of the United 
Kingdom._. 637 
Dykes, Basaltic Sheets, and Isolated Masses of Basalt. 639 
Theory of Disturbances. 639 
Observations at Kilteely. 641 
,, ,, Cromwell’s Hill. 642 
„ „ Canna. 643 
,, „ Titterstone Hill. 647 
,, ,, Brent Tor. 648 
,, „ Builth.. 048 
„ ,, Barmouth. 648 
Basaltic Districts. 649 
Autrim. 650 
Mid-Scotland. 652 
Skye and Mull. 652 
North Wales. 652 
Devonshire and CornAvall. 653 
Wexford and Wicklow. 653 
Donegal. 653 
Pembrokeshire. 653 
Limerick. 653 
Sirmmary of Results. 653 
h 2 
