This is an image of a portion of the 1550 Desceliers map, courtesy of the Library and Archives Canada through the Historical Atlas of Canada site.
Pretty quickly you can recognize what's being depicted: with Florida and the Gulf of Mexico at the top, and “Canada” at the bottom, this is an upside down map of North America, drawn to the best of their knowledge mid-sixteenth century. Various places are recognizable. There's Newfoundland out at the mouth of the Gulf of St. Lawrence, labelled something like Terre Nevfve, and the St. Lawrence River itself coming from a big lake inland.
It's intriguing to see if you can find, on old maps, landmarks with recognizable place names that we use today. For example, Cape Race, at the southeast corner of Newfoundland, is there in the Desceliers map as C: de Raz. Just west of it along Newfoundland's south shore is Cape St. Mary, as C: St Me.
But some of the place names on this map are different. For example Prince Edward Island, the bright red island west of Newfoundland in the Gulf of St. Lawrence, easily recognizable by its crescent shape, is Ye des avenes (Île des avenes, meaning Isle of the Birds?). It's a common story in eastern Canada that names given by the French when it was Nouvelle France were overwritten later by the British when they expelled the French in the eighteenth century. So seeing these early French names is like peeling back the wallpaper to uncover how the room was decorated by the previous owners.
However, this replacement of names is generally not the case in Quebec, which retains most of the original French names. And in fact, looking over at the area up the St. Lawrence, you can see a red island where the river narrows, labelled Ye dorle, probably today's Île d'Orleans, next to the city of Quebec. The big river flowing into the St. Lawrence just downstream, labelled R. de saqnay, and coming from a region labelled Sagne must be the Saguenay River. These are easy connections to make, but they are satisfying.
What really sticks out like a sore thumb here is that big gold island at the mouth of the St. Lawrence. That can only be the Île d'Anticosti, but it's labelled Ye de Taveipel, or Laveipel. What is that? And the lake upstream , perhaps Lake Ontario, or even the smaller Lac de St. Pierre (which his halfway between Montreal and Quebec City) seems to be labelled Le Lac daugonlusme. What is that?
As I started to look further afield for some record of these old names, my interest was sharpened by the discovery that Google returns no results for Taveipel, Laveipel or daugonlusme. I have still not found the answers of what these names meant, but I have learned more.
The Desceliers map, in the St. Lawrence area, had to have been based on information gathered during the voyages of Jacques Cartier. Cartier travelled to New France in 1534, 1535 and 1536. Although he was a successor to Columbus, Cabot, Verrazano, Gomez and others, he was the first European explorer to push up a big river in North America. All of the others had noted rivers, and named them, but had sailed past them, looking only for the large sea passage that would lead to the Orient. Cartier's exploration around the Gulf of St. Lawrence (the water between Newfoundland and the mouth of the St. Lawrence) and up the St. Lawrence River itself marks, in effect, Europeans finally letting go of the dream of a shortcut to China, and taking a closer look at the new world they had on their hands. Exploration of the St. Lawrence, then, predates exploration up the Hudson, or into Chesapeake Bay.
When Cartier went up the St. Lawrence he found two native Iroquois communities: the Stadaconans, who lived near present day Quebec (the narrowing of the river above the red island) , and the Hochlagans, who lived on the island where today's city of Montreal sits. He wintered with the Stadaconans. Both Stadacona and Hochelaga appear on the map repeatedly around the St. Lawrence as ochelaga and estadacone, but not in any one specific place. What seems to read Totunagi, deep inland where another big river joins the St. Lawrence, could be Tutonaguy, which was one of two villages Cartier mentions at Hochelaga. (The Ottawa River joins the St. Lawrence at Montreal.)
A couple days after I began studying this map, I noticed that, on the Desceliers map, on the north shore of the St. Lawrence, across from the gold island, there is a R: de Lareipel. This has to be the same name as the island, but being printed more clearly reveals that I had been reading the island's name wrong: it is Île de Lareipel. Still no Google results though.
The lake up the St. Lawrence (Le Lac daugonlusme) is most likely Lac Saint-Pierre for several reasons. Cartier never made it to Lake Ontario. The splitting of the river at Totunagi corresponds to the way the Ottawa river comes in from the northwest at Montreal. Lac Saint-Pierre is the only lake along the river downstream from Montreal, and, just as on the Desceliers map, there is a major river entering the lake from the south: we call it now the Saint Francois.
Other named features along the St. Lawrence to Saguenay include R[ivier]: de toues and B[aie]: de Lisler. R: de toues must be today's Rivier Saint Maurice. (Toues appear to be a kind of boat.) But Lisler, like Lareipel, does not show up on an internet search.
In the end, this map gives up some names, but others it withholds. It's an intriguing and ongoing puzzle.