Sir,
Drs. Harrington and Speden have offered an interesting defenceReference Harrington and Speden 1 of their theoryReference Harrington and Speden 2 for the ages of the moraines near a lobe of the Taylor Glacier, concerning which we have suggested an alternative hypothesis.Reference Blake and Hollin 3 However, despite the existence of four moraines bordering each of two small neighbouring valley glaciers, and despite the fact that these moraines may correlate with the moraines in Beacon Valley as pictured in the original letter, the absolute ages of all the moraines remain unknown. Until they are known, we feel strongly that their use in the suggested correlation with 19th century moraines in Europe and New ZealandReference Harrington and Speden 2 is unwarranted.
Probably all interested in this discussion will agree that what is needed now is more field study in the area concerned. The work of Drs. Harrington and Speden and their colleagues on the patterned groundReference Harrington and Speden 4 represents one important approach to the problem in question. In addition to the obvious possibility of more C14 dating, lichenometry might show age differences in certain areas. We would also like to suggest that the installation and measurement of a few ablation and movement stakes on this lobe of the Taylor Glacier might indicate whether or not the suggested rate of retreatReference Harrington and Speden 5 is possible under present climatic conditions.
13 March 1961