The eastern limit of the latter group is marked by the Segnas Pass — the most frequented of those connecting the Canton Glarus with the Vorderrhein — beyond which arises a wide-stretching mass of rock and glacier, which is part of the Glarus thrust and culminates at Piz Sardona. This mass is cleft by a deep valley — the Calfeisental: one branch, culminating in the Pizol (2,844 m), extends east over Pfäfers, while another, including the highest peak of the canton of St. Gallen, the Ringelspitz (3,247 m), runs due east to the low Kunkels Pass (1,357 m), separating this range from the Calanda.