Fix up adding just 1 marker. Fixes #60

src/MarkerCluster.js

@@ -185,7 +185,7 @@ L.MarkerCluster = L.Marker.extend({
 	},
 
 	_recursivelyAddChildrenToMap: function (startPos, zoomLevel, bounds) {
-		this._recursively(bounds, 0, zoomLevel,
+		this._recursively(bounds, -1, zoomLevel,
 			function (c) {
 				if (zoomLevel === c._zoom) {
 					return;

src/MarkerClusterGroup.js

@@ -476,6 +476,9 @@ L.MarkerClusterGroup = L.FeatureGroup.extend({
 			gridUnclustered[zoom].addObject(layer, markerPoint);
 		}
 
+		//Didn't get in anything, add us to the top
+		this._topClusterLevel._addChild(layer);
+		layer.__parent = this._topClusterLevel;
 		return;
 	},