1913] The Moraine Systems of Southwestern Ontario. 67 



2. The Milverton Moraine. — This moraine runs on an irregular 

 course north-northeast from London and has been followed to a point 

 five miles northeast of Mount Forest. 1 1 is a slender, lightly built moraine, 

 rather narrow but quite well defined, its relief being generally 20 to 30 

 feet, sometimes 50 feet. It was deposited on land and had a temporary 

 glacial river flowing along its front for a considerable part of its length. 

 This moraine marked the western boundary of "Ontario Island" in the 

 first stage of its existence. The ice front probably retreated to a position 

 a little farther west before readvancing to this moraine. 



3. The Mitchell Moraine. — This is another moraine of the same 

 slender type and strength and was formed at the next halt after the 

 Milverton. Only a fragment of it is now known. 



4. The Lucan Moraine. — This is a third moraine of the same slender 

 type and was formed on a line only a little back of the Mitchell moraine. 

 A fragment of the same length was traced and two or three smaller 

 fragments farther north are believed to belong to it. The Milverton, 

 Mitchell and Lucan moraines all grow faint towards the northeast 

 where they pass up on to the higher part of the plateau. Their relations 

 there have not been determined. 



5. The Seaforth Moraine. — This moraine is somewhat stronger and 

 more bulky than the three preceding it. It is generally slightly wider 

 and higher than the others and the ice at the margin when it was being 

 built was probably thicker than at the times of the earlier three, for 

 this one appears to have been less sensitive to topography. A longer 

 portion has been mapped but a gap remains north of Seaforth. Beyond 

 this it is believed to find continuation in an equally strong moraine 

 which passes through Clifford, Holstein and five miles east of Durham. 

 Farther on it turns sharply to the east and passes through Ceylon and 

 turns a sharp angle toward the southeast two miles west of Singhampton. 

 The Seaforth moraine is strongly developed, especially toward the north- 

 east from Mount Forest. It crosses the highest part of the highland south 

 of Georgian Bay and some of its knolls may be the highest point of this 

 part of Ontario, attaining an altitude of over 1,700 feet above sea level. 

 The moraine itself is generally 50 to 80 feet higher than the plain in front 

 of it and in some places reaches considerably more than 100 feet. It had 

 a large river flowing along its front, beginning at the extreme 

 northeast angle. South of Ceylon this stream had become quite large, 

 and here and west of Mount Forest it filled a wide, shallow depression in 

 front of the moraine with an extensive deposit of gravel and sand. South 

 of Seaforth the same strong drainage line continues and its bed leads to 

 the gravel deposits west of Komoka, to which this stream was probably 

 the largest contributor. 



