You are now at the head of Alpisella valley, at the sources of river Adda.  
The valley bottom appears as a wide, eastward elongated trough, covered by a layer of ancient glacial deposits, upon which grasslands expand; to the north, a quite continuous detrital belt overruns it, built up by debris coming down from the steep dolomitic slopes of Pizzo del Ferro. 
Here and there, waters gently spring out from the soil, then rest, in a series of little ponds and bogs, as if they were thinking about the long way they'll have to travel, towards a far, unknown sea: infact, giving rise all together to Adda river, they will cross the whole Valtellina and the great Como Lake, then will join river Po, and will finally run into the Mediterranean Basin! 
A geologist will explain to you that here, in the axis of Alpisella valley, the alpine Quatervals nappe - as to say the tectonic unit to which the Pizzo del Ferro dolomitic massif belong - overthrusts the tectonic unit of Monte Pettini, known as Ortles nappe; when in contact, a sudden change of permeability causes the flowing out of groundwaters stored into the pervious dolomitic rocks. (da leggere con tono dottorale) 
Actually, waters running down through fractured dolomites of the northern slope of Alpisella Valley, stop suddenly their underground flow against water-tight grey marls underlying the valley bottom; therefore, they have to search for new ways, by running laterally, until they come out through detrital cover, in many little spots scattered over a wide area. This way, they give rise to a creek, which will rapidly increaseing while descending the valley: the little young Adda, ready to start its great course!